Friday, November 14, 2008

Informatica VII

What are the tasks that source qualifier performs?
Join data originating from same source data base.
Filter records when the informatica server reads source data.
Specify an outer join rather than the default inner join specify sorted records.
Select only distinct values from the source.
Creating custom query to issue a special SELECT statement for the informatica server to read source data.
How to join two tables without using the Joiner Transformation.
Itz possible to join the two or more tables by using source qualifier.But provided the tables should have relationship.
When u drag n drop the tables u will getting the source qualifier for each table.Delete all the source qualifiers.Add a common source qualifier for all.Right click on the source qualifier u will find EDIT click on it.Click on the properties tab,u will find sql query in that u can write ur sqls
If you want to create indexes after the load process which transformation you choose?
Its usually not done in the mapping(transformation) level. Its done in session level. Create a command task which will execute a shell script (if Unix) or any other scripts which contains the create index command. Use this command task in the workflow after the session or else, You can create it with a post session command.
What is the use of incremental aggregation? Explain me in brief with an example.
Its a session option. when the informatica server performs incremental aggr. it passes new source data through the mapping and uses historical chache data to perform new aggregation caluculations incrementaly. for performance we will use it.
can any one comment on
significance of oracle 9i in informatica when compared to oracle 8 or 8i.
I mean how is oracle 9i advantageous when compared to oracle 8 or 8i when used in informatica
it's very easy
Actually oracle 8i not allowed userdefined data types
but 9i allows
and then blob,clob allow only 9i not 8i
and more over list partinition is there in 9i only
What happens if you try to create a shortcut to a non-shared folder?
It only creates a copy of it..
What is metadata reporter?
It is a web based application that enables you to run reports againist repository metadata.
With a meta data reporter,You can access information about U’r repository with out having knowledge of sql,transformation language or underlying tables in the repository.
What is polling?
It displays the updated information about the session in the monitor window. The monitor window displays the status of each session when you poll the informatica server.
How do we estimate the number of partitons that a mapping really requires? Is it dependent on the machine configuration?
It depends upon the informatica version we r using. suppose if we r using informatica 6 it supports only 32 partitions where as informatica 7 supports 64 partitions.
How do you decide whether you need ti do aggregations at database level or at Informatica level?
It depends upon our requirment only.If you have good processing database you can create aggregation table or view at database level else its better to use informatica. Here i'm explaing why we need to use informatica.
what ever it may be informatica is a thrid party tool, so it will take more time to process aggregation compared to the database, but in Informatica an option we called "Incremental aggregation" which will help you to update the current values with current values +new values. No necessary to process entire values again and again. Unless this can be done if nobody deleted that cache files. If that happend total aggregation we need to execute on informatica also.

In database we don't have Incremental aggregation facility.
1.can u explain one critical mapping?
2.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
so in this case we will go for unconnected lookup
Discuss which is better among incremental load, Normal Load and Bulk load
It depends on the requirement. Otherwise Incremental load which can be better as it takes onle that data which is not available previously on the target.
What is IQD file?
IQD file is nothing but Impromptu Query Definetion,This file is maily used in Cognos Impromptu tool after creating a imr( report) we save the imr as IQD file which is used while creating a cube in power play transformer.In data source type we select Impromptu Query Definetion.
Which objects are required by the debugger to create a valid debug session?
Intially the session should be valid session.
source, target, lookups, expressions should be availble, min 1 break point should be available for debugger to debug your session.
What are the options in the target session of update strategy transsformatioin?
Update as update
Update as insert
Update esle insert
Truncate table

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