Did u take back Repository backup? how is it store? where?
how did u move code from dev to testing to prod?
What are audit tables?
HOw work will distrubute among team?
What are documents u will receive?
Different type of projects ( develop, migration, production)
How do you upgrade just one mapping?
http://www.youtube.com/watch?v=b2irptGwMNU&feature=fvwrel
http://www.techfaq360.com/informatica_interview_questions.jsp?qid=1004
1. Difference between static cache and dynamic cache?
In case of Dynamic cache when you are inserting a new row it looks at the lookup cache to see if the row existing or not, If not it inserts in the target and cache as well in case of Static cache when you are inserting a new row it checks the cache and writes to the target but not cache
If you cache the lookup table, you can choose to use a dynamic or static cache. By default, the lookup cache remains static and does not change during the session. With a dynamic cache, the Informatica Server inserts or updates rows in the cache during the session. When you cache the target table as the lookup, you can look up values in the target and insert them if they do not exist, or update them if they do.
2. Which transformation should we use to normalize the COBOL and relational sources?
Normalizer Transformation.
When we drag the COBOL source in to the mapping Designer workspace, the normalizer transformation automatically appears, creating input and output ports for every column in the source.
3. What are the join types in joiner transformation?
Normal, Master Outer, Detail Outer, Full Outer
4. In which conditions we can not use joiner transformation (Limitations of joiner transformation)?
No restrictions.
you perform the following task before configuring the joiner transformation configure the transformation to use sorted data and define the join condition to receive sorted data in the same order as the sort origin .
In the conditions; either input pipeline contains an Update Strategy transformation, You connect a Sequence Generator transformation directly before the Joiner transformation
1.Both input pipelines originate from the same Source Qualifier transformation. 2. Both input pipelines originate from the same Normalizer transformation. 3. Both input pipelines originate from the same Joiner transformation. 4. Either input pipeline contains an Update Strategy transformation. 5. We connect a Sequence Generator transformation directly before the Joiner transformation.
5.What is the look up transformation?
Lookup is a passive transformation and used to look up data in a flat file or a relational table.
6.What are the difference between joiner transformation and source qualifier transformation?
1. Source Qualifier Operates only with relational sources within the same schema. Joiner can have either heterogeneous sources or relation sources in different schema 2. Source qualifier requires at least one matching column to perform a join. Joiner joins based on matching port. 3. Additionally, Joiner requires two separate input pipelines and should not have an update strategy or Sequence generator (this is no longer true from Infa 7.2).
7. Why use the lookup transformation?
Used to look up data in a relational table or view.
in Inf7.1, we can get from flat file also
look up is used to perform one of the following task: -to get related value -to perform calculation -to update slowley changing dimension table
generally we use lookup transformation for 1) get a related value from key column value 2) check whether the record already existing in the table 3) slowly changing dimension tables
8. How can you improve session performance in aggregator transformation?
Ya we can use a Sorted Input option to improve the performance. Basically aggregate transformation reduces the performance because it uses caches. Also, By using Incremental Aggregation.
9. What is meant by lookup caches?
Session will read all unique rows from the reference table/ file to fill the local buffer first; then for each row received from up-stream transformation, it tries to match them against the local buffer
Informatica server builts a cache in memory when it process the first row of a cached lookup transformation. alidwh@gmail.com
- When server runs a lookup transformation, the server builds a cache in memory, when it process the first row of data in the transformation. - Server builds the cache and queries it for the each row that enters the transformation. - The server creates index and data cache files in the lookup cache drectory and used the server code page to create the files. - index cache contains conductional values and data cache contains output values
The informatica server builds a cache in memory when it processes the first row of a data in a cached look up transformation. It allocates memory for the cache based on the amount you configure in the transformation or session properties. The informatica server stores condition values in the index cache and output values in the data cache.
10. What is source qualifier transformation?
SQ is an active tramsformation. It performs one of the following task: to join data from the same source database to filtr the rows when Power centre reads source data to perform an outer join to select only distinct values from the source
In source qualifier transformatio a user can defined join conditons,filter the data and eliminating the duplicates. The default source qualifier can over written by the above options, this is known as SQL Override. alidwh@gmail.com
The source qualifier represents the records that the informatica server reads when it runs a session.
When we add a relational or a flat file source definition to a mapping,we need to connect it to a source qualifier transformation.The source qualifier transformation represents the records that the informatica server reads when it runs a session.
11. How the informatica server increases the session performance through partitioning the source?
Partittionig the session improves the session performance by creating multiple connections to sources and targets and loads data in paralel pipe lines
12. What are the settiings that you use to cofigure the joiner transformation?
Master group flow detail group flow join condition type of join
take less no. of rows table as master table, more no of table as detail table and join condition. joiner will put all row from master table into chache and check condition with detail table rows.
1) Master Source 2) Detail Source 3) Type Of Join 4) Condition of Join
13. What are the rank caches?
the informatica server stores group information in an index catche and row data in data catche
when the server runs a session with a Rank transformation, it compares an input row with rows with rows in data cache. If the input row out-ranks a stored row,the Informatica server replaces the stored row with the input row.
During the session ,the informatica server compares an inout row with rows in the datacache. If the input row out-ranks a stored row, the informatica server replaces the stored row with the input row. The informatica server stores group information in an index cache and row data in a data cache.
14. What is Code Page Compatibility?
When two code pages are compatible, the characters encoded in the two code pages are virtually identical.
Compatibility between code pages is used for accurate data movement when the Informatica Sever runs in the Unicode data movement mode. If the code pages are identical, then there will not be any data loss. One code page can be a subset or superset of another. For accurate data movement, the target code page must be a superset of the source code page.
15. How can you create or import flat file definition in to the warehouse designer?
By giving server connection path
Create the file in Warehouse Designer or Import the file from the location it exists or modify the source if the structure is one and the same
first create in source designer then draginto warhouse designer you can't create a flat file target defenition directly ramraj
There is no way to import target definition as file in Informatica designer. So while creating the target definition for a file in the warehouse designer it is created considering it as a table, and then in the session properties of that mapping it is specified as file.
U can not create or import flat file definition in to warehouse designer directly.Instead U must analyze the file in source analyzer,then drag it into the warehouse designer.When U drag the flat file source definition into warehouse designer workspace,the warehouse designer creates a relational target definition not a file definition.If u want to load to a file,configure the session to write to a flat file.When the informatica server runs the session,it creates and loads the flatfile.
16. What is aggregate cache in aggregator transforamtion?
Aggregator Index Cache stores group by values from Group-By ports and Data Cache stores aggregate data based on Group-By ports (variable ports, output ports, non group by ports). When the PowerCenter Server runs a session with an Aggregator transformation, it stores data in memory until it completes the aggregation. If you use incremental aggregation, the PowerCenter Server saves the cache files in the cache file directory.
The aggregator stores data in the aggregate cache until it completes aggregate calculations.When u run a session that uses an aggregator transformation,the informatica server creates index and data caches in memory to process the transformation.If the informatica server requires more space,it stores overflow values in cache files.
17. How can you recognise whether or not the newly added rows in the source are gets insert in the target?
In the type-2 mapping we have three options to recognise the newly added rows. i) Version Number ii) Flag Value iii) Effective Date Range
we can add a count aggregator column to the target and generate it before running the mapping there might couple of different ways to do this or we can run a sql query after running the mapping each time to make sure new data is inserted
From session SrcSuccessRows can be compared with TgtSuccessRows
check the seesion log or check the target table.
18. What are the types of metadata that stores in repository?
Following are the types of metadata that stores in the repository Database connections Global objects Mappings Mapplets Multidimensional metadata Reusable transformations Sessions and batches Short cuts Source definitions Target definitions Transformations.
19. What happens if Informatica server doesn't find the session parameter in the parameter file?
Workflow will fail.
20. Can you access a repository created in previous version of informatica?
We have to migrate the repository from the older version to newer version. Then you can use that repository.
21. Without using ETL tool can u prepare a Data Warehouse and maintain?
Yes we can do that using PL/ SQL or Stored procedures when all the data are in the same databases. If you have source as flat files you can?t do it through PL/ SQL or stored procedures.
22. How do you identify the changed records in operational data?
In my project source system itself sending us the new records and changed records from the last 24 hrs.
23. Why couldn't u go for Snowflake schema?
Snowflake is less performance while compared to star schema, because it will contain multi joins while retrieving the data.
Snowflake is preferred in two cases,
If you want to load the data into more hierarchical levels of information example yearly, quarterly, monthly, daily, hourly, minutes of information. Prefer snowflake.
Whenever u found input data contain more low cardinality elements. You have to prefer snowflake schema. Low cardinality example: sex , marital Status, etc., Low cardinality means no of distinct records is very less while compared to total number of the records,
24. Name some measures in your fact table?
Sales amount.
25. How many dimension tables did you had in your project and name some dimensions (columns)?
Product Dimension : Product Key, Product id, Product Type, Product name, Batch Number.
Distributor Dimension: Distributor key, Distributor Id, Distributor Location,
Customer Dimension : Customer Key, Customer Id, CName, Age, status, Address, Contact
Account Dimension : Account Key, Acct id, acct type, Location, Balance,
26. How many Fact and Dimension tables are there in your project?
In my module (Sales) we have 4 Dimensions and 1 fact table.
27. How many Data marts are there in your project?
There are 4 Data marts, Sales, Marketing, Finance and HR. In my module we are handling only sales data mart.
28. What is the daily data volume (in GB/records)? What is the size of the data extracted in the extraction process?
Approximately average 40k records per file per day. Daily we will get 8 files from 8 source systems.
29. What is the size of the database in your project?
Based on the client's database, it might be in GB's.
30. What is meant by clustering?
It will join two (or more) tables in single buffer, will retrieve the data easily.
31. Whether are not the session can be considered to have a heterogeneous target is determined?
It will consider (there is no primary key and foreign key relationship)
32. Under what circumstance can a target definition are edited from the mapping designer. Within the mapping where that target definition is being used?
We can't edit the target definition in mapping designer. we can edit the target in warehouse designer only. But in our projects, we haven't edited any of the targets. if any change required to the target definition we will inform to the DBA to make the change to the target definition and then we will import again. We don't have any permission to the edit the source and target tables.
33. Can a source qualifier be used to perform a outer join when joining 2 database?
No, we can't join two different databases join in SQL Override.
34. If u r source is flat file with delimited operator.when next time u want change that delimited operator where u can make?
In the session properties go to mappings and click on the target instance click set file properties we have to change the delimited option.
35. If index cache file capacity is 2MB and datacache is 1 MB. If you enter the data of capacity for index is 3 MB and data is 2 MB. What will happen?
Nothing will happen based the buffer size exists in the server we can change the cache sizes. Max size of cache is 2 GB.
36. Difference between next value and current value ports in sequence generator?
Assume that they r both connected to the input of another transformer?
It will gives values like nextvalue 1, currval 0.
37. How does dynamic cache handle the duplicates rows?
Dynamic Cache will gives the flags to the records while inserting to the cache it will gives flags to the records, like new record assigned to insert flag as "0", updated record is assigned to updated flag as "1", No change record assigned to rejected flag as "2"
38. How will u find whether your mapping is correct or not without connecting session?
Through debugging option.
39. If you are using aggregator transformation in your mapping at that time your source contain dimension or fact?
According to requirements, we can use aggregator transformation. There is no limitation for the aggregator. We should use source as dimension or fact.
40. My input is oracle and my target is flat file shall I load it? How?
Yes, Create flat file based on the structure match with oracle table in warehouse designer than develop the mapping according requirement and map to that target flat file. Target file is created in TgtFiles directory in the server system.
41. for a session, can I use 3 mappings?
No, for one session there should be only one mapping. We have to create separate session for each mapping.
42. Type of loading procedures?
Load procedures are two types 1) Normal load 2) bulk loads if you are talking about informatica level. If you are talking about project load procedures based on the project requirement. Daily loads or weekly loads.
43. Are you involved in high level r low level design? What is meant by that high level design n low level design?
Low Level design:
Requirements should be in the excel format which describes field to field validations and business logic needs to present. Mostly onsite team will do this Low Level design.
High Level Design:
Describes the informatica flow chart from source qualifier to target simply we can say flow chart of the informatica mapping. Developer will do this design document.
44. what r the dimension load methods?
Daily loads or weekly loads based on the project requirement.
45. where we are using lkp t/r source to stage or stage to target?
Depend on the requirement. There is no rule we have to use in this stage only.
46. How will you do SQL tuning?
We can do SQL tuning using Oracle Optimizer, TOAD software.
47. did u use any other tools for scheduling purpose other than workflow manager or pmcmd?
Using third party tools like "Control M".
48. What is SQL mass updating?
A)
Update (select hs1.col1 as hs1_col1
, hs1.col2 as hs1_col2
, hs1.col3 as hs1_col3
, hs2.col1 as hs2_col1
, hs2.col2 as hs2_col2
, hs2.col3 as hs2_col3
From hs1, hs2
Where hs1.sno = hs2.sno)
set hs1_col1 = hs2_col1
, hs1_col2 = hs2_col2
, hs1_col3 = hs2_col3;
49. what is unbounded exception in source qualifier?
"TE_7020 Unbound field in Source Qualifier" when running session
A) Problem Description:
When running a session the session fails with the following error:
TE_7020 Unbound field in Source Qualifier "
Solution:
This error will occur when there is an inconsistency between the Source Qualifier and the source table.
Either there is a field in the Source Qualifier that is not in the physical table or there is a column
of the source object that has no link to the corresponding port in the Source Qualifier.
To resolve this, re-import the source definition into the Source Analyzer in Designer.
Bring the new Source definition into the mapping.This will also re-create the Source Qualifier.
Connect the new Source Qualifier to the rest of the mapping as before.
50. Using unconnected lookup how we you remove nulls n duplicates?
We can't handle nulls and duplicates in the unconnected lookup. We can handle in dynamic connected lookup.
51. I have 20 lookup, 10 joiners, 1 normalizer how will you improve the session performance?
We have to calculate lookup & joiner caches size
52. What is version controlling?
It is the method to differentiate the old build and the new build after changes made to the existing code. For the old code v001 and next time u have to increase the version number as v002 like that. In my last company we haven't use any version controlling. We just delete the old build and replace with the new code.
We don't maintain version controlling in informatica. We are maintaining the code in VSS (Virtual visual Source) that is the software with maintain the code with versioning. Whenever client made change request came once the production starts we have to create another build.
53. How is the Sequence Generator transformation different from other transformations?
The Sequence Generator is unique among all transformations because we cannot add, edit, or delete its default ports (NEXTVAL and CURRVAL).
Unlike other transformations we cannot override the Sequence Generator transformation properties at the session level. This protecxts the integrity of the sequence values generated.
54.What are the advantages of Sequence generator? Is it necessary, if so why?
We can make a Sequence Generator reusable, and use it in multiple mappings. We might reuse a Sequence Generator when we perform multiple loads to a single target.
For example, if we have a large input file that we separate into three sessions running in parallel, we can use a Sequence Generator to generate primary key values. If we use different Sequence Generators, the Informatica Server might accidentally generate duplicate key values. Instead, we can use the same reusable Sequence Generator for all three sessions to provide a unique value for each target row.
55. What are the uses of a Sequence Generator transformation?
We can perform the following tasks with a Sequence Generator transformation:
o Create keys
o Replace missing values
o Cycle through a sequential range of numbers
56.What is the difference between connected lookup and unconnected lookup?
Connected Lookup
Receives input values directly from the pipeline.
We can use a dynamic or static cache
Supports user-defined default values
Unconnected Lookup
Receives input values from the result of a :LKP expression in another transformation.
We can use a static cache
Does not support user-defined default values
57. What is a Lookup transformation and what are its uses?
We use a Lookup transformation in our mapping to look up data in a relational table, view or synonym.
We can use the Lookup transformation for the following purposes:
Get a related value. For example, if our source table includes employee ID, but we want to include the employee name in our target table to make our summary data easier to read.
Perform a calculation. Many normalized tables include values used in a calculation, such as gross sales per invoice or sales tax, but not the calculated value (such as net sales).
Update slowly changing dimension tables. We can use a Lookup transformation to determine whether records already exist in the target.
58.What is a lookup table?
The lookup table can be a single table, or we can join multiple tables in the same database using a lookup query override. The Informatica Server queries the lookup table or an in-memory cache of the table for all incoming rows into the Lookup transformation.
If your mapping includes heterogeneous joins, we can use any of the mapping sources or mapping targets as the lookup table.
59. Where do you define update strategy?
We can set the Update strategy at two different levels:
? Within a session. When you configure a session, you can instruct the Informatica Server to either treat all records in the same way (for example, treat all records as inserts), or use instructions coded into the session mapping to flag records for different database operations.
? Within a mapping. Within a mapping, you use the Update Strategy transformation to flag records for insert, delete, update, or reject.
60. What is Update Strategy?
When we design our data warehouse, we need to decide what type of information to store in targets. As part of our target table design, we need to determine whether to maintain all the historic data or just the most recent changes.
The model we choose constitutes our update strategy, how to handle changes to existing records.
Update strategy flags a record for update, insert, delete, or reject. We use this transformation when we want to exert fine control over updates to a target, based on some condition we apply. For example, we might use the Update Strategy transformation to flag all customer records for update when the mailing address has changed, or flag all employee records for reject for people no longer working for the company
61. What are the tools provided by Designer?
The Designer provides the following tools:
? Source Analyzer. Use to import or create source definitions for flat file, XML, Cobol, ERP, and relational sources.
? Warehouse Designer. Use to import or create target definitions.
? Transformation Developer. Use to create reusable transformations.
? Mapplet Designer. Use to create mapplets.
? Mapping Designer. Use to create mappings.
62. What are the different types of Commit intervals?
The different commit intervals are:
1)Target-based commit. The Informatica Server commits data based on the number of target rows and the key constraints on the target table. The commit point also depends on the buffer block size and the commit interval.
2) Source-based commit. The Informatica Server commits data based on the number of source rows. The commit point is the commit interval you configure in the session properties.
63. What is Event-Based Scheduling?
When you use event-based scheduling, the Informatica Server starts a session when it locates the specified indicator file. To use event-based scheduling, you need a shell command, script, or batch file to create an indicator file when all sources are available. The file must be created or sent to a directory local to the Informatica Server. The file can be of any format recognized by the Informatica Server operating system. The Informatica Server deletes the indicator file once the session starts.
Use the following syntax to ping the Informatica Server on a UNIX system:
pmcmd ping [{user_name | %user_env_var} {password | %password_env_var}] [hostname:]portno
Use the following syntax to start a session or batch on a UNIX system:
pmcmd start {user_name | %user_env_var} {password | %password_env_var} [hostname:]portno [folder_name:]{session_name | batch_name} [:pf=param_file] session_flag wait_flag
Use the following syntax to stop a session or batch on a UNIX system:
pmcmd stop {user_name | %user_env_var} {password | %password_env_var} [hostname:]portno[folder_name:]{session_name | batch_name} session_flag
Use the following syntax to stop the Informatica Server on a UNIX system:
pmcmd stopserver {user_name | %user_env_var} {password | %password_env_var} [hostname:]portno
64.I have the Administer Repository Privilege, but I cannot access a repository using the Repository Manager.
To perform administration tasks in the Repository Manager with the Administer Repository privilege, you must also have the default privilege Browse Repository. You can assign Browse Repository directly to a user login, or you can inherit Browse Repository from a group.
65. My privileges indicate I should be able to edit objects in the repository, but I cannot edit any metadata.
You may be working in a folder with restrictive permissions. Check the folder permissions to see if you belong to a group whose privileges are restricted by the folder owner.
66. How does read permission affect the use of the command line program, pmcmd?
To use pmcmd, you do not need to view a folder before starting a session or batch within the folder. Therefore, you do not need read permission to start sessions or batches with pmcmd. You must, however, know the exact name of the session or batch and the folder in which it exists.
With pmcmd, you can start any session or batch in the repository if you have the Session Operator privilege or execute permission on the folder.
67. I do not want a user group to create or edit sessions and batches, but I need them to access the Server Manager to stop the Informatica Server.
To permit a user to access the Server Manager to stop the Informatica Server, you must grant them both the Create Sessions and Batches, and Administer Server privileges. To restrict the user from creating or editing sessions and batches, you must restrict the user's write permissions on a folder level.
Alternatively, the user can use pmcmd to stop the Informatica Server with the Administer Server privilege alone.
68. I created a new group and removed the Browse Repository privilege from the group. Why does every user in the group still have that privilege?
Privileges granted to individual users take precedence over any group restrictions. Browse Repository is a default privilege granted to all new users and groups. Therefore, to remove the privilege from users in a group, you must remove the privilege from the group, and every user in the group.
69. After creating users and user groups, and granting different sets of privileges, I find that none of the repository users can perform certain tasks, even the Administrator.
Repository privileges are limited by the database privileges granted to the database user who created the repository. If the database user (one of the default users created in the Administrators group) does not have full database privileges in the repository database, you need to edit the database user to allow all privileges in the database.
70. What are the different types of locks?
There are five kinds of locks on repository objects:
? Read lock. Created when you open a repository object in a folder for which you do not have write permission. Also created when you open an object with an existing write lock.
? Write lock. Created when you create or edit a repository object in a folder for which you have write permission.
? Execute lock. Created when you start a session or batch, or when the Informatica Server starts a scheduled session or batch.
? Fetch lock. Created when the repository reads information about repository objects from the database.
? Save lock. Created when you save information to the repository.
71. What is Local Repository?
Each local repository in the domain can connect to the global repository and use objects in its shared folders. A folder in a local repository can be copied to other local repositories while keeping all local and global shortcuts intact.
72. What is a Global repository?
The centralized repository in a domain, a group of connected repositories. Each domain can contain one global repository. The global repository can contain common objects to be shared throughout the domain through global shortcuts. Once created, you cannot change a global repository to a local repository. You can promote an existing local repository to a global repository.
73. When should you create the dynamic data store? Do you need a DDS at all?
To decide whether you should create a dynamic data store (DDS), consider the following issues:
Answer1: How much data do you need to store in the DDS? The one principal advantage of data marts is the selectivity of information included in it. Instead of a copy of everything potentially relevant from the OLTP database and flat files, data marts contain only the information needed to answer specific questions for a specific audience (for example, sales performance data used by the sales division). A dynamic data store is a hybrid of the galactic warehouse and the individual data mart, since it includes all the data needed for all the data marts it supplies. If the dynamic data store contains nearly as much information as the OLTP source, you might not need the intermediate step of the dynamic data store. However, if the dynamic data store includes substantially less than all the data in the source databases and flat files, you should consider creating a DDS staging area.
Answer2: What kind of standards do you need to enforce in your data marts? Creating a DDS is an important technique in enforcing standards. If data marts depend on the DDS for information, you can provide that data in the range and format you want everyone to use. For example, if you want all data marts to include the same information on customers, you can put all the data needed for this standard customer profile in the DDS. Any data mart that reads customer data from the DDS should include all the information in this profile.
Answer3: How often do you update the contents of the DDS? If you plan to frequently update data in data marts, you need to update the contents of the DDS at least as often as you update the individual data marts that the DDS feeds. You may find it easier to read data directly from source databases and flat file systems if it becomes burdensome to update the DDS fast enough to keep up with the needs of individual data marts. Or, if particular data marts need updates significantly faster than others, you can bypass the DDS for these fast update data marts.
Answer4: Is the data in the DDS simply a copy of data from source systems, or do you plan to reformat this information before storing it in the DDS? One advantage of the dynamic data store is that, if you plan on reformatting information in the same fashion for several data marts, you only need to format it once for the dynamic data store. Part of this question is whether you keep the data normalized when you copy it to the DDS.
Answer5: How often do you need to join data from different systems? On occasion, you may need to join records queried from different databases or read from different flat file systems. The more frequently you need to perform this type of heterogeneous join, the more advantageous it would be to perform all such joins within the DDS, then make the results available to all data marts that use the DDS as a source.
74. What are Shortcuts?
We can create shortcuts to objects in shared folders. Shortcuts provide the easiest way to reuse objects. We use a shortcut as if it were the actual object, and when we make a change to the original object, all shortcuts inherit the change.
Shortcuts to folders in the same repository are known as local shortcuts. Shortcuts to the global repository are called global shortcuts.
We use the Designer to create shortcuts.
75. What are Sessions and Batches?
Sessions and batches store information about how and when the Informatica Server moves data through mappings. You create a session for each mapping you want to run. You can group several sessions together in a batch. Use the Server Manager to create sessions and batches.
76. Why do we need SQL overrides in Lookup transformations?
In order to lookup more than one value from one table, we go for SQL overrides in Lookups.
77. Which ETL tool is more preferable Informatica or Data Stage and why?
Preference of an ETL tool depends on affordability and functionality. It is mostly a tradeoff between the price and feature. While Informatica has been a market leader since the past many years, DataStage is beginning to pick up momentum.
78. What is the use of auxiliary mapping?
Auxiliary mapping reflects change in one table whenever there is a change in the other table.
79. What is authenticator?
It validates user name and password to access the PowerCenter repository.
80. How do we create primary key only on odd numbers?
To create primary key, we use sequence generator and set the 'Increment by' property of sequence generator to 2
81. What is the difference between source qualifier transformation and application source qualifier transformation?
Source qualifier transformation extracts data from RDBMS or from a single flat file system. Application source qualifier transformation extracts data from application sources like ERP.
82. What is the use of control break statements?
They execute a set of codes within the loop and endloop.
83. What is the use of tracing levels in transformation?
Tracing levels store information about mapping and transformations.
84. What are the different types of OLAP TECHNOLOGY?
Online Analytical process is of three types, they are MOLAP, HOLAP and ROLAP. MOLAP Mulidimensional online analytical process. It is used for fast retrival of data and also for slicing and dicing operations. It plays a vital role in easing complex calculations. ROLAP Relational online analytical process. It has the ability to handle large amount of data. HOLAP Hybrid online analytical process. It is a combination of both HOLAP and MOLAP.
85. What is Data Modeling? What are the different types of Data Modeling?
Data modeling is a process of creating data models. In other words, it is structuring and organizing data in a uniform manner where constraints are placed within the structure.The Data structure formed are maintained in a database management system. The Different types of Data Modeling are: 1. Dimension Modelling 2. E-R Modelling
86. What is the need of building a data warehouse?
The need of building a data warehouse is that, it acts as a storage fill for a large amount of data. It also provides end user access to a wide varity of data, helps in analyzing data more effectively and also in generating reports. It acts as a huge repository for integrated information.
87. What is drill-down and drill-up?
Both drill-down and drill-up are used to explore different levels of dimensionally modeled data. Drill-down allows the users view lower level (i.e. more detailed level) of data and drill-up allows the users to view higher level (i.e. more summarized level) of data.
88. What is cube?
Cube is a multidimensional representation of data. It is used for analysis purpose. A cube gives multiple views of data.
89. Where did u use the Unix shell scripts in informatica projects?
To concatinate 2 or more Flat files, Workflow scheduling, File watcher script.
90. how to u generate surrogate keys for tables with more than 2 billion records (surrogate key is a primary key field).
Dont use sequence generator, But use a Expression variable increment & look up transformation to get the last value used from target.
91. how do u propagate date coloumn to a flat file, if u need format to be DD-MON-YYYY?
Using To_date function before loading to flat file
92. If you use sorted I/P option in Aggregator but gave it Unsorted I/P then what will happen?
Fails the session with error messg 'Expecting keys to be ascending'.
93. If i have 100 rows given as I/P to aggregator & want 100 rows as O/P then how can u achieve that?(none of the coloumns are primary key)
Aggregator is an active transformation. So you can't expect it to give exact number of output rows for all input rows you have given to it.
94.If i have 100 rows given as I/P to aggregator & want just 100th row as O/P then how can u achieve that?
If you dont select any group by port in ports tab of aggregator transformation then informatica is only going to give last row as output for all the numerous records given to it as input.
95. What are all the conditions (=, Not Between) you have in Lookup & in Joiner?
Lookup (=, !=, >=, <=, >, <), Joiner (= only )
96. If i had a flat file, Can i over ride SQL in Source Qualifier or Lookup?
You can never over ride a SQL Query when you are playing with flat files.
97. If i have a flat file target, When i click it in the Workflow manager, What all properties would i get?
File Writer, Merge Partionned file, Merge File name, Merge File Dir, O/P file name, O/P file dir, Reject file name, Reject file dir.
98. What is the use of Return Port & Output port in Lookup Transformation?
By default all the ports in lookup transformation are Look up & O/P ports. Return ports are only used in Unconnected lookup & You need have atleast 1 Output port in Connected lookup. (cant explain in detail here...)
99. If i have used 2 update strategys in my mapping..1 for insert & other for delete, then i changed target option in session properties from datadriven to delete...then how is my mapping going to perform ? (all deletes or insert & delete)
Workflow succeds but you get an error mesg in logs saying target did not permit to insert & all the records marked for inserts are loaded into badfile.
100. Scenario for using dynamic lookup
Ans: Loading data from flat file to a table, But the data in file is violating primary key constraint of table due to
duplicate data
101. Why you need surrogate key instead of OLTP primary key, Tell a scenario where it’s mandatory to use surrogate key
Ans: If prod key is numeric before & OLTP People decided to go for alphanumeric, we may have to change all data types. in warehouse where that key is involved. So best to keep it away from business defined values, To track SCD
102. What’s the default & Max size of data cache?
20 MB, 2 GB
103. What is materialized view, how it’s going to improve performance.
Ans: It creates physical table unlike normal view
104. When you use bitmap indexes
Ans: when cardinality is low, distinct rows <> Newfile.txt
105. what is implicit cursor & explicit cursor in oracle?
Ans: Implicit cursor is a defined for every query executed. Its attributes can be retrieved after executing query using sql as prefix Ex: sql%rowcount. Explicit cursor is the cursors what we define manually.
106. what is the cursor attributes
Ans:%found
%notfound
%rowcount
107. how would you stop session row if a value for particular column is matched to a given value
Ans: use abort function of informatica in expression transformation
108. how about error function in informatica
Ans: it logs the error message you defined in the session log if particular condition is satisfied
109. levels of logs you can maintain in informatica sessions
Ans: Terse,Normal,And Verbose
110. how to run sequential sessions only if previous session loads at least one row in target
Ans: Defined a link condition between sessions with TgtSuccessrows>0
111. difference between max & greatest functions in oracle
Ans: Greatest gives greatest of 2 values, max is the max value of all available values
112. how you get number of rows returned by lookup when a condition matches
Ans: Define a new column & use SQL override with count(*)
113. how can you configure informatica workflow to run only on first working day of the month
Ans: Define a calendar & go with a session or script.
114. when you go for sql overrides
Ans: When you want to share some processing load with Database, When it’s more effective
115. what are types of triggers, difference between row level & statement level trigger
Ans: after/before statement level/row level insert/delete/update
116. Can you join 2 tables using SQL override in Lookup transformation
Ans: Yes
117. If a session fails, What are the steps you follow in resolving it
Ans: check session logs with various tracing levels.
118. How you filter records in TOAD
Ans: Use filter icon & Add rule on columns
119. What is persistent cache in lookup transformation.
Ans: Its remains even after session run, useful in incremental aggregation
120. how did you implement incremental extraction
Ans: Mostly using set variable or some way of truncating stage tables or use parameter files
121. tell me about 'set variable' function in informatica
Ans: Set a value to variable depending on the last row processed
122. if you change properties in session, which one takes preference, is it mapping level or session level
Ans: Session Level
123. Syntax for defining a parameter in parameter file
Ans: Folder - workflow - session – mapplet
124. How would you identify why a record is rejected
Ans: (D,O,N,T Indicators)
125.
how did u move code from dev to testing to prod?
What are audit tables?
HOw work will distrubute among team?
What are documents u will receive?
Different type of projects ( develop, migration, production)
How do you upgrade just one mapping?
http://www.youtube.com/watch?v=b2irptGwMNU&feature=fvwrel
http://www.techfaq360.com/informatica_interview_questions.jsp?qid=1004
1. Difference between static cache and dynamic cache?
In case of Dynamic cache when you are inserting a new row it looks at the lookup cache to see if the row existing or not, If not it inserts in the target and cache as well in case of Static cache when you are inserting a new row it checks the cache and writes to the target but not cache
If you cache the lookup table, you can choose to use a dynamic or static cache. By default, the lookup cache remains static and does not change during the session. With a dynamic cache, the Informatica Server inserts or updates rows in the cache during the session. When you cache the target table as the lookup, you can look up values in the target and insert them if they do not exist, or update them if they do.
2. Which transformation should we use to normalize the COBOL and relational sources?
Normalizer Transformation.
When we drag the COBOL source in to the mapping Designer workspace, the normalizer transformation automatically appears, creating input and output ports for every column in the source.
3. What are the join types in joiner transformation?
Normal, Master Outer, Detail Outer, Full Outer
4. In which conditions we can not use joiner transformation (Limitations of joiner transformation)?
No restrictions.
you perform the following task before configuring the joiner transformation configure the transformation to use sorted data and define the join condition to receive sorted data in the same order as the sort origin .
In the conditions; either input pipeline contains an Update Strategy transformation, You connect a Sequence Generator transformation directly before the Joiner transformation
1.Both input pipelines originate from the same Source Qualifier transformation. 2. Both input pipelines originate from the same Normalizer transformation. 3. Both input pipelines originate from the same Joiner transformation. 4. Either input pipeline contains an Update Strategy transformation. 5. We connect a Sequence Generator transformation directly before the Joiner transformation.
5.What is the look up transformation?
Lookup is a passive transformation and used to look up data in a flat file or a relational table.
6.What are the difference between joiner transformation and source qualifier transformation?
1. Source Qualifier Operates only with relational sources within the same schema. Joiner can have either heterogeneous sources or relation sources in different schema 2. Source qualifier requires at least one matching column to perform a join. Joiner joins based on matching port. 3. Additionally, Joiner requires two separate input pipelines and should not have an update strategy or Sequence generator (this is no longer true from Infa 7.2).
7. Why use the lookup transformation?
Used to look up data in a relational table or view.
in Inf7.1, we can get from flat file also
look up is used to perform one of the following task: -to get related value -to perform calculation -to update slowley changing dimension table
generally we use lookup transformation for 1) get a related value from key column value 2) check whether the record already existing in the table 3) slowly changing dimension tables
8. How can you improve session performance in aggregator transformation?
Ya we can use a Sorted Input option to improve the performance. Basically aggregate transformation reduces the performance because it uses caches. Also, By using Incremental Aggregation.
9. What is meant by lookup caches?
Session will read all unique rows from the reference table/ file to fill the local buffer first; then for each row received from up-stream transformation, it tries to match them against the local buffer
Informatica server builts a cache in memory when it process the first row of a cached lookup transformation. alidwh@gmail.com
- When server runs a lookup transformation, the server builds a cache in memory, when it process the first row of data in the transformation. - Server builds the cache and queries it for the each row that enters the transformation. - The server creates index and data cache files in the lookup cache drectory and used the server code page to create the files. - index cache contains conductional values and data cache contains output values
The informatica server builds a cache in memory when it processes the first row of a data in a cached look up transformation. It allocates memory for the cache based on the amount you configure in the transformation or session properties. The informatica server stores condition values in the index cache and output values in the data cache.
10. What is source qualifier transformation?
SQ is an active tramsformation. It performs one of the following task: to join data from the same source database to filtr the rows when Power centre reads source data to perform an outer join to select only distinct values from the source
In source qualifier transformatio a user can defined join conditons,filter the data and eliminating the duplicates. The default source qualifier can over written by the above options, this is known as SQL Override. alidwh@gmail.com
The source qualifier represents the records that the informatica server reads when it runs a session.
When we add a relational or a flat file source definition to a mapping,we need to connect it to a source qualifier transformation.The source qualifier transformation represents the records that the informatica server reads when it runs a session.
11. How the informatica server increases the session performance through partitioning the source?
Partittionig the session improves the session performance by creating multiple connections to sources and targets and loads data in paralel pipe lines
12. What are the settiings that you use to cofigure the joiner transformation?
Master group flow detail group flow join condition type of join
take less no. of rows table as master table, more no of table as detail table and join condition. joiner will put all row from master table into chache and check condition with detail table rows.
1) Master Source 2) Detail Source 3) Type Of Join 4) Condition of Join
13. What are the rank caches?
the informatica server stores group information in an index catche and row data in data catche
when the server runs a session with a Rank transformation, it compares an input row with rows with rows in data cache. If the input row out-ranks a stored row,the Informatica server replaces the stored row with the input row.
During the session ,the informatica server compares an inout row with rows in the datacache. If the input row out-ranks a stored row, the informatica server replaces the stored row with the input row. The informatica server stores group information in an index cache and row data in a data cache.
14. What is Code Page Compatibility?
When two code pages are compatible, the characters encoded in the two code pages are virtually identical.
Compatibility between code pages is used for accurate data movement when the Informatica Sever runs in the Unicode data movement mode. If the code pages are identical, then there will not be any data loss. One code page can be a subset or superset of another. For accurate data movement, the target code page must be a superset of the source code page.
15. How can you create or import flat file definition in to the warehouse designer?
By giving server connection path
Create the file in Warehouse Designer or Import the file from the location it exists or modify the source if the structure is one and the same
first create in source designer then draginto warhouse designer you can't create a flat file target defenition directly ramraj
There is no way to import target definition as file in Informatica designer. So while creating the target definition for a file in the warehouse designer it is created considering it as a table, and then in the session properties of that mapping it is specified as file.
U can not create or import flat file definition in to warehouse designer directly.Instead U must analyze the file in source analyzer,then drag it into the warehouse designer.When U drag the flat file source definition into warehouse designer workspace,the warehouse designer creates a relational target definition not a file definition.If u want to load to a file,configure the session to write to a flat file.When the informatica server runs the session,it creates and loads the flatfile.
16. What is aggregate cache in aggregator transforamtion?
Aggregator Index Cache stores group by values from Group-By ports and Data Cache stores aggregate data based on Group-By ports (variable ports, output ports, non group by ports). When the PowerCenter Server runs a session with an Aggregator transformation, it stores data in memory until it completes the aggregation. If you use incremental aggregation, the PowerCenter Server saves the cache files in the cache file directory.
The aggregator stores data in the aggregate cache until it completes aggregate calculations.When u run a session that uses an aggregator transformation,the informatica server creates index and data caches in memory to process the transformation.If the informatica server requires more space,it stores overflow values in cache files.
17. How can you recognise whether or not the newly added rows in the source are gets insert in the target?
In the type-2 mapping we have three options to recognise the newly added rows. i) Version Number ii) Flag Value iii) Effective Date Range
we can add a count aggregator column to the target and generate it before running the mapping there might couple of different ways to do this or we can run a sql query after running the mapping each time to make sure new data is inserted
From session SrcSuccessRows can be compared with TgtSuccessRows
check the seesion log or check the target table.
18. What are the types of metadata that stores in repository?
Following are the types of metadata that stores in the repository Database connections Global objects Mappings Mapplets Multidimensional metadata Reusable transformations Sessions and batches Short cuts Source definitions Target definitions Transformations.
19. What happens if Informatica server doesn't find the session parameter in the parameter file?
Workflow will fail.
20. Can you access a repository created in previous version of informatica?
We have to migrate the repository from the older version to newer version. Then you can use that repository.
21. Without using ETL tool can u prepare a Data Warehouse and maintain?
Yes we can do that using PL/ SQL or Stored procedures when all the data are in the same databases. If you have source as flat files you can?t do it through PL/ SQL or stored procedures.
22. How do you identify the changed records in operational data?
In my project source system itself sending us the new records and changed records from the last 24 hrs.
23. Why couldn't u go for Snowflake schema?
Snowflake is less performance while compared to star schema, because it will contain multi joins while retrieving the data.
Snowflake is preferred in two cases,
If you want to load the data into more hierarchical levels of information example yearly, quarterly, monthly, daily, hourly, minutes of information. Prefer snowflake.
Whenever u found input data contain more low cardinality elements. You have to prefer snowflake schema. Low cardinality example: sex , marital Status, etc., Low cardinality means no of distinct records is very less while compared to total number of the records,
24. Name some measures in your fact table?
Sales amount.
25. How many dimension tables did you had in your project and name some dimensions (columns)?
Product Dimension : Product Key, Product id, Product Type, Product name, Batch Number.
Distributor Dimension: Distributor key, Distributor Id, Distributor Location,
Customer Dimension : Customer Key, Customer Id, CName, Age, status, Address, Contact
Account Dimension : Account Key, Acct id, acct type, Location, Balance,
26. How many Fact and Dimension tables are there in your project?
In my module (Sales) we have 4 Dimensions and 1 fact table.
27. How many Data marts are there in your project?
There are 4 Data marts, Sales, Marketing, Finance and HR. In my module we are handling only sales data mart.
28. What is the daily data volume (in GB/records)? What is the size of the data extracted in the extraction process?
Approximately average 40k records per file per day. Daily we will get 8 files from 8 source systems.
29. What is the size of the database in your project?
Based on the client's database, it might be in GB's.
30. What is meant by clustering?
It will join two (or more) tables in single buffer, will retrieve the data easily.
31. Whether are not the session can be considered to have a heterogeneous target is determined?
It will consider (there is no primary key and foreign key relationship)
32. Under what circumstance can a target definition are edited from the mapping designer. Within the mapping where that target definition is being used?
We can't edit the target definition in mapping designer. we can edit the target in warehouse designer only. But in our projects, we haven't edited any of the targets. if any change required to the target definition we will inform to the DBA to make the change to the target definition and then we will import again. We don't have any permission to the edit the source and target tables.
33. Can a source qualifier be used to perform a outer join when joining 2 database?
No, we can't join two different databases join in SQL Override.
34. If u r source is flat file with delimited operator.when next time u want change that delimited operator where u can make?
In the session properties go to mappings and click on the target instance click set file properties we have to change the delimited option.
35. If index cache file capacity is 2MB and datacache is 1 MB. If you enter the data of capacity for index is 3 MB and data is 2 MB. What will happen?
Nothing will happen based the buffer size exists in the server we can change the cache sizes. Max size of cache is 2 GB.
36. Difference between next value and current value ports in sequence generator?
Assume that they r both connected to the input of another transformer?
It will gives values like nextvalue 1, currval 0.
37. How does dynamic cache handle the duplicates rows?
Dynamic Cache will gives the flags to the records while inserting to the cache it will gives flags to the records, like new record assigned to insert flag as "0", updated record is assigned to updated flag as "1", No change record assigned to rejected flag as "2"
38. How will u find whether your mapping is correct or not without connecting session?
Through debugging option.
39. If you are using aggregator transformation in your mapping at that time your source contain dimension or fact?
According to requirements, we can use aggregator transformation. There is no limitation for the aggregator. We should use source as dimension or fact.
40. My input is oracle and my target is flat file shall I load it? How?
Yes, Create flat file based on the structure match with oracle table in warehouse designer than develop the mapping according requirement and map to that target flat file. Target file is created in TgtFiles directory in the server system.
41. for a session, can I use 3 mappings?
No, for one session there should be only one mapping. We have to create separate session for each mapping.
42. Type of loading procedures?
Load procedures are two types 1) Normal load 2) bulk loads if you are talking about informatica level. If you are talking about project load procedures based on the project requirement. Daily loads or weekly loads.
43. Are you involved in high level r low level design? What is meant by that high level design n low level design?
Low Level design:
Requirements should be in the excel format which describes field to field validations and business logic needs to present. Mostly onsite team will do this Low Level design.
High Level Design:
Describes the informatica flow chart from source qualifier to target simply we can say flow chart of the informatica mapping. Developer will do this design document.
44. what r the dimension load methods?
Daily loads or weekly loads based on the project requirement.
45. where we are using lkp t/r source to stage or stage to target?
Depend on the requirement. There is no rule we have to use in this stage only.
46. How will you do SQL tuning?
We can do SQL tuning using Oracle Optimizer, TOAD software.
47. did u use any other tools for scheduling purpose other than workflow manager or pmcmd?
Using third party tools like "Control M".
48. What is SQL mass updating?
A)
Update (select hs1.col1 as hs1_col1
, hs1.col2 as hs1_col2
, hs1.col3 as hs1_col3
, hs2.col1 as hs2_col1
, hs2.col2 as hs2_col2
, hs2.col3 as hs2_col3
From hs1, hs2
Where hs1.sno = hs2.sno)
set hs1_col1 = hs2_col1
, hs1_col2 = hs2_col2
, hs1_col3 = hs2_col3;
49. what is unbounded exception in source qualifier?
"TE_7020 Unbound field in Source Qualifier" when running session
A) Problem Description:
When running a session the session fails with the following error:
TE_7020 Unbound field
Solution:
This error will occur when there is an inconsistency between the Source Qualifier and the source table.
Either there is a field in the Source Qualifier that is not in the physical table or there is a column
of the source object that has no link to the corresponding port in the Source Qualifier.
To resolve this, re-import the source definition into the Source Analyzer in Designer.
Bring the new Source definition into the mapping.This will also re-create the Source Qualifier.
Connect the new Source Qualifier to the rest of the mapping as before.
50. Using unconnected lookup how we you remove nulls n duplicates?
We can't handle nulls and duplicates in the unconnected lookup. We can handle in dynamic connected lookup.
51. I have 20 lookup, 10 joiners, 1 normalizer how will you improve the session performance?
We have to calculate lookup & joiner caches size
52. What is version controlling?
It is the method to differentiate the old build and the new build after changes made to the existing code. For the old code v001 and next time u have to increase the version number as v002 like that. In my last company we haven't use any version controlling. We just delete the old build and replace with the new code.
We don't maintain version controlling in informatica. We are maintaining the code in VSS (Virtual visual Source) that is the software with maintain the code with versioning. Whenever client made change request came once the production starts we have to create another build.
53. How is the Sequence Generator transformation different from other transformations?
The Sequence Generator is unique among all transformations because we cannot add, edit, or delete its default ports (NEXTVAL and CURRVAL).
Unlike other transformations we cannot override the Sequence Generator transformation properties at the session level. This protecxts the integrity of the sequence values generated.
54.What are the advantages of Sequence generator? Is it necessary, if so why?
We can make a Sequence Generator reusable, and use it in multiple mappings. We might reuse a Sequence Generator when we perform multiple loads to a single target.
For example, if we have a large input file that we separate into three sessions running in parallel, we can use a Sequence Generator to generate primary key values. If we use different Sequence Generators, the Informatica Server might accidentally generate duplicate key values. Instead, we can use the same reusable Sequence Generator for all three sessions to provide a unique value for each target row.
55. What are the uses of a Sequence Generator transformation?
We can perform the following tasks with a Sequence Generator transformation:
o Create keys
o Replace missing values
o Cycle through a sequential range of numbers
56.What is the difference between connected lookup and unconnected lookup?
Connected Lookup
Receives input values directly from the pipeline.
We can use a dynamic or static cache
Supports user-defined default values
Unconnected Lookup
Receives input values from the result of a :LKP expression in another transformation.
We can use a static cache
Does not support user-defined default values
57. What is a Lookup transformation and what are its uses?
We use a Lookup transformation in our mapping to look up data in a relational table, view or synonym.
We can use the Lookup transformation for the following purposes:
Get a related value. For example, if our source table includes employee ID, but we want to include the employee name in our target table to make our summary data easier to read.
Perform a calculation. Many normalized tables include values used in a calculation, such as gross sales per invoice or sales tax, but not the calculated value (such as net sales).
Update slowly changing dimension tables. We can use a Lookup transformation to determine whether records already exist in the target.
58.What is a lookup table?
The lookup table can be a single table, or we can join multiple tables in the same database using a lookup query override. The Informatica Server queries the lookup table or an in-memory cache of the table for all incoming rows into the Lookup transformation.
If your mapping includes heterogeneous joins, we can use any of the mapping sources or mapping targets as the lookup table.
59. Where do you define update strategy?
We can set the Update strategy at two different levels:
? Within a session. When you configure a session, you can instruct the Informatica Server to either treat all records in the same way (for example, treat all records as inserts), or use instructions coded into the session mapping to flag records for different database operations.
? Within a mapping. Within a mapping, you use the Update Strategy transformation to flag records for insert, delete, update, or reject.
60. What is Update Strategy?
When we design our data warehouse, we need to decide what type of information to store in targets. As part of our target table design, we need to determine whether to maintain all the historic data or just the most recent changes.
The model we choose constitutes our update strategy, how to handle changes to existing records.
Update strategy flags a record for update, insert, delete, or reject. We use this transformation when we want to exert fine control over updates to a target, based on some condition we apply. For example, we might use the Update Strategy transformation to flag all customer records for update when the mailing address has changed, or flag all employee records for reject for people no longer working for the company
61. What are the tools provided by Designer?
The Designer provides the following tools:
? Source Analyzer. Use to import or create source definitions for flat file, XML, Cobol, ERP, and relational sources.
? Warehouse Designer. Use to import or create target definitions.
? Transformation Developer. Use to create reusable transformations.
? Mapplet Designer. Use to create mapplets.
? Mapping Designer. Use to create mappings.
62. What are the different types of Commit intervals?
The different commit intervals are:
1)Target-based commit. The Informatica Server commits data based on the number of target rows and the key constraints on the target table. The commit point also depends on the buffer block size and the commit interval.
2) Source-based commit. The Informatica Server commits data based on the number of source rows. The commit point is the commit interval you configure in the session properties.
63. What is Event-Based Scheduling?
When you use event-based scheduling, the Informatica Server starts a session when it locates the specified indicator file. To use event-based scheduling, you need a shell command, script, or batch file to create an indicator file when all sources are available. The file must be created or sent to a directory local to the Informatica Server. The file can be of any format recognized by the Informatica Server operating system. The Informatica Server deletes the indicator file once the session starts.
Use the following syntax to ping the Informatica Server on a UNIX system:
pmcmd ping [{user_name | %user_env_var} {password | %password_env_var}] [hostname:]portno
Use the following syntax to start a session or batch on a UNIX system:
pmcmd start {user_name | %user_env_var} {password | %password_env_var} [hostname:]portno [folder_name:]{session_name | batch_name} [:pf=param_file] session_flag wait_flag
Use the following syntax to stop a session or batch on a UNIX system:
pmcmd stop {user_name | %user_env_var} {password | %password_env_var} [hostname:]portno[folder_name:]{session_name | batch_name} session_flag
Use the following syntax to stop the Informatica Server on a UNIX system:
pmcmd stopserver {user_name | %user_env_var} {password | %password_env_var} [hostname:]portno
64.I have the Administer Repository Privilege, but I cannot access a repository using the Repository Manager.
To perform administration tasks in the Repository Manager with the Administer Repository privilege, you must also have the default privilege Browse Repository. You can assign Browse Repository directly to a user login, or you can inherit Browse Repository from a group.
65. My privileges indicate I should be able to edit objects in the repository, but I cannot edit any metadata.
You may be working in a folder with restrictive permissions. Check the folder permissions to see if you belong to a group whose privileges are restricted by the folder owner.
66. How does read permission affect the use of the command line program, pmcmd?
To use pmcmd, you do not need to view a folder before starting a session or batch within the folder. Therefore, you do not need read permission to start sessions or batches with pmcmd. You must, however, know the exact name of the session or batch and the folder in which it exists.
With pmcmd, you can start any session or batch in the repository if you have the Session Operator privilege or execute permission on the folder.
67. I do not want a user group to create or edit sessions and batches, but I need them to access the Server Manager to stop the Informatica Server.
To permit a user to access the Server Manager to stop the Informatica Server, you must grant them both the Create Sessions and Batches, and Administer Server privileges. To restrict the user from creating or editing sessions and batches, you must restrict the user's write permissions on a folder level.
Alternatively, the user can use pmcmd to stop the Informatica Server with the Administer Server privilege alone.
68. I created a new group and removed the Browse Repository privilege from the group. Why does every user in the group still have that privilege?
Privileges granted to individual users take precedence over any group restrictions. Browse Repository is a default privilege granted to all new users and groups. Therefore, to remove the privilege from users in a group, you must remove the privilege from the group, and every user in the group.
69. After creating users and user groups, and granting different sets of privileges, I find that none of the repository users can perform certain tasks, even the Administrator.
Repository privileges are limited by the database privileges granted to the database user who created the repository. If the database user (one of the default users created in the Administrators group) does not have full database privileges in the repository database, you need to edit the database user to allow all privileges in the database.
70. What are the different types of locks?
There are five kinds of locks on repository objects:
? Read lock. Created when you open a repository object in a folder for which you do not have write permission. Also created when you open an object with an existing write lock.
? Write lock. Created when you create or edit a repository object in a folder for which you have write permission.
? Execute lock. Created when you start a session or batch, or when the Informatica Server starts a scheduled session or batch.
? Fetch lock. Created when the repository reads information about repository objects from the database.
? Save lock. Created when you save information to the repository.
71. What is Local Repository?
Each local repository in the domain can connect to the global repository and use objects in its shared folders. A folder in a local repository can be copied to other local repositories while keeping all local and global shortcuts intact.
72. What is a Global repository?
The centralized repository in a domain, a group of connected repositories. Each domain can contain one global repository. The global repository can contain common objects to be shared throughout the domain through global shortcuts. Once created, you cannot change a global repository to a local repository. You can promote an existing local repository to a global repository.
73. When should you create the dynamic data store? Do you need a DDS at all?
To decide whether you should create a dynamic data store (DDS), consider the following issues:
Answer1: How much data do you need to store in the DDS? The one principal advantage of data marts is the selectivity of information included in it. Instead of a copy of everything potentially relevant from the OLTP database and flat files, data marts contain only the information needed to answer specific questions for a specific audience (for example, sales performance data used by the sales division). A dynamic data store is a hybrid of the galactic warehouse and the individual data mart, since it includes all the data needed for all the data marts it supplies. If the dynamic data store contains nearly as much information as the OLTP source, you might not need the intermediate step of the dynamic data store. However, if the dynamic data store includes substantially less than all the data in the source databases and flat files, you should consider creating a DDS staging area.
Answer2: What kind of standards do you need to enforce in your data marts? Creating a DDS is an important technique in enforcing standards. If data marts depend on the DDS for information, you can provide that data in the range and format you want everyone to use. For example, if you want all data marts to include the same information on customers, you can put all the data needed for this standard customer profile in the DDS. Any data mart that reads customer data from the DDS should include all the information in this profile.
Answer3: How often do you update the contents of the DDS? If you plan to frequently update data in data marts, you need to update the contents of the DDS at least as often as you update the individual data marts that the DDS feeds. You may find it easier to read data directly from source databases and flat file systems if it becomes burdensome to update the DDS fast enough to keep up with the needs of individual data marts. Or, if particular data marts need updates significantly faster than others, you can bypass the DDS for these fast update data marts.
Answer4: Is the data in the DDS simply a copy of data from source systems, or do you plan to reformat this information before storing it in the DDS? One advantage of the dynamic data store is that, if you plan on reformatting information in the same fashion for several data marts, you only need to format it once for the dynamic data store. Part of this question is whether you keep the data normalized when you copy it to the DDS.
Answer5: How often do you need to join data from different systems? On occasion, you may need to join records queried from different databases or read from different flat file systems. The more frequently you need to perform this type of heterogeneous join, the more advantageous it would be to perform all such joins within the DDS, then make the results available to all data marts that use the DDS as a source.
74. What are Shortcuts?
We can create shortcuts to objects in shared folders. Shortcuts provide the easiest way to reuse objects. We use a shortcut as if it were the actual object, and when we make a change to the original object, all shortcuts inherit the change.
Shortcuts to folders in the same repository are known as local shortcuts. Shortcuts to the global repository are called global shortcuts.
We use the Designer to create shortcuts.
75. What are Sessions and Batches?
Sessions and batches store information about how and when the Informatica Server moves data through mappings. You create a session for each mapping you want to run. You can group several sessions together in a batch. Use the Server Manager to create sessions and batches.
76. Why do we need SQL overrides in Lookup transformations?
In order to lookup more than one value from one table, we go for SQL overrides in Lookups.
77. Which ETL tool is more preferable Informatica or Data Stage and why?
Preference of an ETL tool depends on affordability and functionality. It is mostly a tradeoff between the price and feature. While Informatica has been a market leader since the past many years, DataStage is beginning to pick up momentum.
78. What is the use of auxiliary mapping?
Auxiliary mapping reflects change in one table whenever there is a change in the other table.
79. What is authenticator?
It validates user name and password to access the PowerCenter repository.
80. How do we create primary key only on odd numbers?
To create primary key, we use sequence generator and set the 'Increment by' property of sequence generator to 2
81. What is the difference between source qualifier transformation and application source qualifier transformation?
Source qualifier transformation extracts data from RDBMS or from a single flat file system. Application source qualifier transformation extracts data from application sources like ERP.
82. What is the use of control break statements?
They execute a set of codes within the loop and endloop.
83. What is the use of tracing levels in transformation?
Tracing levels store information about mapping and transformations.
84. What are the different types of OLAP TECHNOLOGY?
Online Analytical process is of three types, they are MOLAP, HOLAP and ROLAP. MOLAP Mulidimensional online analytical process. It is used for fast retrival of data and also for slicing and dicing operations. It plays a vital role in easing complex calculations. ROLAP Relational online analytical process. It has the ability to handle large amount of data. HOLAP Hybrid online analytical process. It is a combination of both HOLAP and MOLAP.
85. What is Data Modeling? What are the different types of Data Modeling?
Data modeling is a process of creating data models. In other words, it is structuring and organizing data in a uniform manner where constraints are placed within the structure.The Data structure formed are maintained in a database management system. The Different types of Data Modeling are: 1. Dimension Modelling 2. E-R Modelling
86. What is the need of building a data warehouse?
The need of building a data warehouse is that, it acts as a storage fill for a large amount of data. It also provides end user access to a wide varity of data, helps in analyzing data more effectively and also in generating reports. It acts as a huge repository for integrated information.
87. What is drill-down and drill-up?
Both drill-down and drill-up are used to explore different levels of dimensionally modeled data. Drill-down allows the users view lower level (i.e. more detailed level) of data and drill-up allows the users to view higher level (i.e. more summarized level) of data.
88. What is cube?
Cube is a multidimensional representation of data. It is used for analysis purpose. A cube gives multiple views of data.
89. Where did u use the Unix shell scripts in informatica projects?
To concatinate 2 or more Flat files, Workflow scheduling, File watcher script.
90. how to u generate surrogate keys for tables with more than 2 billion records (surrogate key is a primary key field).
Dont use sequence generator, But use a Expression variable increment & look up transformation to get the last value used from target.
91. how do u propagate date coloumn to a flat file, if u need format to be DD-MON-YYYY?
Using To_date function before loading to flat file
92. If you use sorted I/P option in Aggregator but gave it Unsorted I/P then what will happen?
Fails the session with error messg 'Expecting keys to be ascending'.
93. If i have 100 rows given as I/P to aggregator & want 100 rows as O/P then how can u achieve that?(none of the coloumns are primary key)
Aggregator is an active transformation. So you can't expect it to give exact number of output rows for all input rows you have given to it.
94.If i have 100 rows given as I/P to aggregator & want just 100th row as O/P then how can u achieve that?
If you dont select any group by port in ports tab of aggregator transformation then informatica is only going to give last row as output for all the numerous records given to it as input.
95. What are all the conditions (=, Not Between) you have in Lookup & in Joiner?
Lookup (=, !=, >=, <=, >, <), Joiner (= only )
96. If i had a flat file, Can i over ride SQL in Source Qualifier or Lookup?
You can never over ride a SQL Query when you are playing with flat files.
97. If i have a flat file target, When i click it in the Workflow manager, What all properties would i get?
File Writer, Merge Partionned file, Merge File name, Merge File Dir, O/P file name, O/P file dir, Reject file name, Reject file dir.
98. What is the use of Return Port & Output port in Lookup Transformation?
By default all the ports in lookup transformation are Look up & O/P ports. Return ports are only used in Unconnected lookup & You need have atleast 1 Output port in Connected lookup. (cant explain in detail here...)
99. If i have used 2 update strategys in my mapping..1 for insert & other for delete, then i changed target option in session properties from datadriven to delete...then how is my mapping going to perform ? (all deletes or insert & delete)
Workflow succeds but you get an error mesg in logs saying target did not permit to insert & all the records marked for inserts are loaded into badfile.
100. Scenario for using dynamic lookup
Ans: Loading data from flat file to a table, But the data in file is violating primary key constraint of table due to
duplicate data
101. Why you need surrogate key instead of OLTP primary key, Tell a scenario where it’s mandatory to use surrogate key
Ans: If prod key is numeric before & OLTP People decided to go for alphanumeric, we may have to change all data types. in warehouse where that key is involved. So best to keep it away from business defined values, To track SCD
102. What’s the default & Max size of data cache?
20 MB, 2 GB
103. What is materialized view, how it’s going to improve performance.
Ans: It creates physical table unlike normal view
104. When you use bitmap indexes
Ans: when cardinality is low, distinct rows <> Newfile.txt
105. what is implicit cursor & explicit cursor in oracle?
Ans: Implicit cursor is a defined for every query executed. Its attributes can be retrieved after executing query using sql as prefix Ex: sql%rowcount. Explicit cursor is the cursors what we define manually.
106. what is the cursor attributes
Ans:%found
%notfound
%rowcount
107. how would you stop session row if a value for particular column is matched to a given value
Ans: use abort function of informatica in expression transformation
108. how about error function in informatica
Ans: it logs the error message you defined in the session log if particular condition is satisfied
109. levels of logs you can maintain in informatica sessions
Ans: Terse,Normal,And Verbose
110. how to run sequential sessions only if previous session loads at least one row in target
Ans: Defined a link condition between sessions with TgtSuccessrows>0
111. difference between max & greatest functions in oracle
Ans: Greatest gives greatest of 2 values, max is the max value of all available values
112. how you get number of rows returned by lookup when a condition matches
Ans: Define a new column & use SQL override with count(*)
113. how can you configure informatica workflow to run only on first working day of the month
Ans: Define a calendar & go with a session or script.
114. when you go for sql overrides
Ans: When you want to share some processing load with Database, When it’s more effective
115. what are types of triggers, difference between row level & statement level trigger
Ans: after/before statement level/row level insert/delete/update
116. Can you join 2 tables using SQL override in Lookup transformation
Ans: Yes
117. If a session fails, What are the steps you follow in resolving it
Ans: check session logs with various tracing levels.
118. How you filter records in TOAD
Ans: Use filter icon & Add rule on columns
119. What is persistent cache in lookup transformation.
Ans: Its remains even after session run, useful in incremental aggregation
120. how did you implement incremental extraction
Ans: Mostly using set variable or some way of truncating stage tables or use parameter files
121. tell me about 'set variable' function in informatica
Ans: Set a value to variable depending on the last row processed
122. if you change properties in session, which one takes preference, is it mapping level or session level
Ans: Session Level
123. Syntax for defining a parameter in parameter file
Ans: Folder - workflow - session – mapplet
124. How would you identify why a record is rejected
Ans: (D,O,N,T Indicators)
125.
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