Que 1)This is a scenario in which the source has 2 cols 10 A 10 A 20 C 30 D 40 E 20 C And there should be 2 targets one to show the duplicate values and another target for distinct rows. T1 T2 10 A 10 A 20 C 20 C 30 D Which transformation can be used to load data into target? 40 E
Ans : 1) Source – SQ with group by on key column – Aggregator (do a count on key column) - Router O/P group condition (if count_key>1) - connect Router O/P group to Target2(duplicate) and default group to Target1(distinct)
2) Source – SQ – First stream : sorter (select distinct check box) – connect to Target 1 Stream 2 : Aggregator (do a count on key column) – filter (if count_key>1) – Target 2
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Que 2) What is the need and when do we use a dynamic lookup cache?
Implementing Dynamic cache in the lookup transformation comes under performance tuning side. If your mapping has lookup on target u can implement dynamic cache.
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Que 3) How can you improve the performance of Aggregate transformation?
We can improve the aggregator’s performances in the following ways
1. Send sorted input.
2. Increase aggregator cache size .i.e. Index cache and data cache.
3. Give input/output what you need in the transformation.i.e reduce number of input and output ports.
Use Sorter Transformation to sort input in aggregator properties filter the records before
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Que 4)What is the method of loading 5 flat files of having same structure to a single target and which transformations I can use? union transformation, otherwise write all file paths of five files in one file and use this file in session properties as indirect ------
Que 5) Can u explain one critical mapping? performance issue which one is better? whether connected lookup tranformation or unconnected one? it depends on your data and the type of operation u r doing.
If u need to calculate a value for all the rows or for the maximum rows coming out of the source then go for a connected lookup.
Or,if it is not so then go for unconnectd lookup.
Specially in conditional case like,we have to get value for a field 'customer' from order tabel or from customer_data table,on the basis of following rule:
If customer_name is null then ,customer=customer_data.ustomer_Id otherwise customer=order.customer_name. so in this case we will go for unconnected lookup
Dimesions are 1. SCD 2. Rapidly changing Dimensions 3. junk Dimensions 4. Large Dimensions 5. Degenerated Dimensions 6. Conformed Dimensions.
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Que 6) How do you create single lookup transformation using multiple tables?
Write a override sql query. Adjust the ports as per the sql query.
By writing SQL override and specifying joins in the SQL override.
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Que 7) How to load time dimension?
We can use SCD Type 1/2/3 to load any Dimensions based on the requirement.
We can also use procedure to populate Time Dimension
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Que 8) After dragging the ports of three sources (sql server, oracle, Informix) to a single Source qualifier, can u map these three ports directly to target?
You cannot pull heterogeneous transformations into a single Source Qualifier. You have to use separate SQs and then use Joiner to join the sources.
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Que 9) How can u work with remote database in informatica? Did u work directly by using remote connections?
You can work with remote,
But you have to : configure FTP Connection details
IP address
User authentication
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Que 10) What is power center repository?
Answer : Standalone repository: A repository that functions individually, unrelated and unconnected to other repositories.
Global repository (PowerCenter only): 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.
Local repository (PowerCenter only): A repository within a domain that is not the global repository. Each local repository in the domain can connect to the global repository and use objects in its shared folders.
Power Center repository is used to store informatica's meta data . Information such as mapping name, location, target definitions, source definitions, transformation and flow is stored as meta data in the repository.
The informatica client and server access the repository to save and retrieve metadata.
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Mapplet : set of transformations that are reusable.
Reusuable Transformation: Single transformation which is reusable.
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Que 11) what is difference between partioning of relational target and partitioning of file targets?
Partition's can be done on both relational and flat files. Informatica supports following partitions
1. Database partitioning
2. Round Robin
3. Pass-through
4. Hash-Key partitioning
5. Key Range partitioning
All these are applicable for relational targets. For flat file only database partitioning is not applicable.
Informatica supports Nway partitioning. U can just specify the name of the target file and create the partitions, rest will be taken care by informatica session.
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Que 12) What is parameter file?
When you start a workflow, you can optionally enter the directory and name of a parameter file The Informatica Server runs the workflow using the parameters in the file you specify.
For UNIX shell users, enclose the parameter file name in single quotes:
-paramfile '$PMRootDir/myfile.txt'
For Windows command prompt users, the parameter file name cannot have beginning or trailing spaces. If the name includes spaces, enclose the file name in double quotes:
-paramfile ”$PMRootDirmy file.txt”
Note: When you write a pmcmd command that includes a parameter file located on another machine, use the backslash () with the dollar sign ($). This ensures that the machine where the variable is defined expands the server variable. running wrkflow from command prompt : pmcmd startworkflow -uv USERNAME -pv PASSWORD -s SALES:6258 -f east -w wSalesAvg -paramfile '$PMRootDir/myfile.txt'
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Que 13) What is batch and describe about types of batches?
Batch -- is a group of sessions
There are two types of batches 1. Concurrent (all running at the same time) 2. Sequential (one aft the other, based on conditions) ------
Que 14) Can u copy the session to a different folder or repository?
In addition, you can copy the workflow from the Repository manager. This will automatically copy the mapping, associated source, targets and session to the target folder.
Yes it is possible. For copying a session to a folder in the same repository or to another in a different repository, we can use the repository manager ( which is client side tool).Simply by just dragging the session to the target destination, the session will be copied.
------Que 15) Why we use partitioning the session in informatica?
Performance can be improved by processing data in parallel in a single session by creating multiple partitions of the pipeline.
Informatica server can achieve high performance by partitioning the pipeline and performing the extract, transformation, and load for each partition in parallel.
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Que 16) How the informatica server increases the session performance through partitioning the source?
For relational sources informatica server creates multiple connections for each partition of a single source and extracts separate range of data for each connection.Informatica server reads multiple partitions of a single source concurently.Similarly for loading also informatica server creates multiple connections to the target and loads partitions of data concurrently.
For XML and file sources, informatica server reads multiple files concurently.For loading the data informatica server creates a separate file for each partition (of a source file).U can choose to merge the targets.
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Que 17) Can u generate reports in Informatcia?
It is an ETL tool, you could not make reports from here, but you can generate metadata report that is not going to be used for business analysis
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Que 18) How can u recognize whether a row which is newly added in the source gets insert in the target?
Ans : If u want to get the info of all the insert statements and Updates you need to use session log file where you configure it to verbose.
You will get complete set of data which record was inserted and which was not. ------Que 19) what r the different types of Type2 dimension mapping?
Ans: Type2 1. Version number 2. Flag 3. Date ------
Que 20) what r the types of mapping in Getting Started Wizard?
Ans:
1. Simple Pass through 2. Slowly Growing Target
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Que 21) What r the options in the target session of update strategy transformation?
Ans : Update as Insert:
This option specified all the update records from source to be flagged as inserts in the target. In other words, instead of updating the records in the target they are inserted as new records.
Update else Insert:
This option enables informatica to flag the records either for update if they are old or insert, if they are new records from source. insert, update, delete, insert as update, update else insert. update as update.
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Que 22) What joins does the Joiner transformation support
The Joiner transformation supports the following join types, which you set in the Properties tab:
Normal (Default) Master Outer Detail Outer Full Outer ------
Que 23) What r the tasks that source qualifier perform?
Join data originating from the same source database. You can join two or more tables with primary-foreign key relationships by linking the sources to one Source Qualifier.
Filter records when the Informatica Server reads source data. If you include a filter condition, the Informatica Server adds a WHERE clause to the default query.
Specify an outer join rather than the default inner join. If you include a user-defined join, the Informatica Server replaces the join information specified by the metadata in the SQL query. Specify sorted ports. If you specify a number for sorted ports, the Informatica Server adds an ORDER BY clause to the default SQL query.
Select only distinct values from the source. If you choose Select Distinct, the Informatica Server adds a SELECT DISTINCT statement to the default SQL query.
Create a custom query to issue a special SELECT statement for the Informatica Server to read source data. For example, you might use a custom query to perform aggregate calculations or execute a stored procedure.
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Que 24) What r the types of groups in Router transformation?
Router has
1. Input group - where we have ports from the source, it has input port only.
2. User defined group : here we can create n number of groups according to our Business requirements. it has out put port only.
3. Default grope: what ever the records are not matching the user defined group automatically captured by this group and send back to the user for analysis.
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Que 25) Differences between connected and unconnected lookup?
Connected lookup Unconnected lookup
1) Receives input values directly Receives input values from the result of a lkp from the pipe line. expression in another transformation.
2) U can use a dynamic or static cache U can use a static cache.
3) Cache includes all lookup columns used Cache includes all lookup out put ports in the in the mapping lookup condition and the lookup/return port.
4) Support user defined default values Does not support user defined default values
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Que 26) What r the differences between joiner transformation and source qualifier
Source qualifier – Homogeneous source Joiner – Heterogeneous source Joiner condition executed with in the informatica staging layer source qualifier condition excited with in the database level
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Que 27) What is aggregate cache in aggregator transformation? When you run a workflow 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.