Friday, November 14, 2008

Questions VII

why did u use update stategy in your application?
Update Strategy is used to drive the data to be Inert, Update and Delete depending upon some condition. You can do this on session level tooo but there you cannot define any condition.For eg: If you want to do update and insert in one will create two flows and will make one as insert and one as update depending upon some condition.Refer : Update Strategy in Transformation Guide for more information

What r the options in the target session of update strategy transsformatioin?
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.

How do we do unit testing in informatica?
How do we load data in informatica ?
Unit testing are of two types
1. Quantitaive testing
2.Qualitative testing
1.First validate the mapping
2.Create session on themapping and then run workflow.
Once the session is succeeded the right click on session and go for statistics tab.
There you can see how many number of source rows are applied and how many number of rows loaded in to targets and how many number of rows rejected.This is called Quantitative testing.
If once rows are successfully loaded then we will go for qualitative testing.
1.Take the DATM(DATM means where all business rules are mentioned to the corresponding source columns) and check whether the data is loaded according to the DATM in to target table.If any data is not loaded according to the DATM then go and check in the code and rectify it.
This is called Qualitative testing.
This is what a devloper will do in Unit Testing.

How can u complete unrcoverable sessions?
Under certain circumstances, when a session does not complete, you need to truncate the target tables and run the session from the beginning. Run the session from the
beginning when the Informatica Server cannot run recovery or when running recovery might result in inconsistent data.

What is the difference between connected and unconnected stored procedures.
The unconnected Stored Procedure transformation is not connected directly to the flow of the mapping. It either runs before or after the session, or is called by an expression in another transformation in the mapping.
The flow of data through a mapping in connected mode also passes through the Stored Procedure transformation. All data entering the transformation through the input ports affects the stored procedure. You should use a connected Stored Procedure transformation when you need data from an input port sent as an input parameter to the stored procedure, or the results of a stored procedure sent as an output parameter to another transformation.
Can we eliminate duplicate rows by using filter and router transformation ?if so explain me in detail .
U can use SQL query for uniqness if the source is Relational
But if the source is Flat file then u should use Shorter or Aggregatot transformation

Can u start a batches with in a batch?
U can not. If u want to start batch that resides in a batch,create a new independent batch and copy the necessary sessions into the new batch.
in the concept of mapping parameters and variables, the variable value will be saved to the repository after the completion of the session and the next time when u run the session, the server takes the saved variable value in the repository and starts assigning the next value of the saved value. for example i ran a session and in the end it stored a value of 50 to the time when i run the session, it should start with the value of 70. not with the value of 51.
how to do this.
u can do onething after running the mapping,, in workflow manager
right clickon the session u will get a menu, in that go for persistant values, there u will find the last value stored in the repository regarding to mapping variable. then remove it and put ur desired one, run the session... i hope ur task will be done

How can U create or import flat file definition in to the warehouse designer?
U can create flat file definition in warehouse the warehouse designer,u can create new target: select the type as flat file. save it and u can enter various columns for that created target by editing its properties.Once the target is created, save it. u can import it from the mapping designer.

What r the different types of Type2 dimension maping?
1. Version number
2. Flag

What are the mapings that we use for slowly changing dimension table?
Type1: Rows containing changes to existing dimensions are updated in the target by overwriting the existing dimension. In the Type 1 Dimension mapping, all rows contain
current dimension data.
Use the Type 1 Dimension mapping to update a slowly changing dimension table when you do not need to keep any previous versions of dimensions in the table.
Type 2: The Type 2 Dimension Data mapping inserts both new and changed dimensions into the target. Changes are tracked in the target table by versioning the primary
key and creating a version number for each dimension in the table.
Use the Type 2 Dimension/Version Data mapping to update a slowly changing dimension table when you want to keep a full history of dimension data in the table. Version numbers and versioned primary keys track the order of changes to each dimension.
Type 3: The Type 3 Dimension mapping filters source rows based on user-defined comparisons and inserts only those found to be new dimensions to the target. Rows
containing changes to existing dimensions are updated in the target. When updating an existing dimension, the Informatica Server saves existing data in different columns
of the same row and replaces the existing data with the updates.

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