This document discusses several scenarios involving Informatica mappings and transformations: 1) Loading data from an Oracle table to a target table while removing the first and last rows, noting that SQL does not inherently define row order unless explicitly sorted. 2) Creating loops in lookups using a COUNT query in the lookup override. 3) Avoiding having a lookup refresh after each mapping session by making it persistent across mappings. 4) Updating a target table without a key by defining matching source columns as a virtual primary key in the target.

1. /*Informatica Good Scenarios */
•
• I have a source which is oracle table, while loading into target table, it should
remove 1st and last records and should load the rest of the data
Important Notice:
As you are pulling from a database table, there is no notion of any particular row being the
first or last. SQL does not imply any sequence to the rows returned unless you explicitly
sort them. Therefore, any process that is based on the return order of rows that does not
explicily order them will be unreliable.
Which leads to the question... what's special about the first and last rows
• To Create Loops in Lookups:
You just have to use basic select count(*) query in the lup override.
1) Create a lup on the source table with name lkp_CNT.
2) Create two columns in the lup one for returning count and another for input to the ULP.
3) Let the columns be COUNT_ID(Integer - O,L,R) and In_Port(Integer - I)
4) Condition on the lup COUNT_ID != In_Port
5) Now generate the query in the SQL override and edit it as follows.
SELECT count(*) as COUNT_ID FROM EMP_REC
6) Now call this ULUP from expression as :LKP.lkp_CNT(0). This will return the count.
Hope I have answered your question.
-Bala
• Avoiding Lookup to get updated during the workflow
Descritption:
I have created 3 different mappings which load the data into the same target table and
placed these mapping in the same workflow. Before loading the data, it does a lookup on
the target table to see if that particular year exists. Since the three mapping are loading
into the same target table, how should I avoid getting lookup updated after the end of the
first session, so that when the second and third session runs the remaining data is loaded
successfully??
Set the lookup as persistant in the two subsequent mappings and make sure the file name
is the same. The mappings will use the existing lookup file and not refresh the data
• Update Trasformation:
Description: I want to update a table based on the input.
Target table is not having any key. It as total 7 columns and I need to look on 4

2. columns and if there is a match then update only the remaing 3 columns.
I SOLUTION: Just define all the four columns in the target definition as primary key.
Now set treat source as update and target property as updae as update.
Now when you run the session...based on the match of the four key columns it will
perform update.
If your target has some primary key but still you need to update the table based on non
key columns, then you need to go for target update override.
But in your case you can follow my first suggestion.
I haven't tried it....but hope it will work.
Let me know if you find any problem.
II SOLUTION:
In your target designer create keys on those 4 columns (but do not create it on database
level).The target will be now updated based on the keys you have virtually created on the
metadata level.To verify the same you can go to update override and check the default
statement generated.Remove the override after you check that the statement is generated
correctly.
Hope that helps
So when we use virtual key there is no need of update transformation in our mapping?
Please advise
Ya naveen,
You do need a update startegy transformation,If your requirement is only needed for
update. Just in the session properties set the property treat source rows as update after
setting the virtuall keys in mapping.