Reverse the Contents of Flat File – Informatica
Q1) I have a flat file, want to reverse the contents of the flat file which means the first record should come as last record and last record should come as first record and load into the target file.
As an example consider the source flat file data as
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The target flat file data should look as
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Solution:
Follow the below steps for creating the mapping logic
Create a new mapping.
Drag the flat file source into the mapping.
Create an expression transformation and drag the ports of source qualifier transformation into the expression transformation.
Create the below additional ports in the expression transformation and assign the corresponding expressions
Variable port: v_count = v_count+1 Output port o_count = v_count
Now create a sorter transformation and drag the ports of expression transformation into it.
In the sorter transformation specify the sort key as o_count and sort order as DESCENDING.
Drag the target definition into the mapping and connect the ports of sorter transformation to the target.
Q2) Load the header record of the flat file into first target, footer record into second target and the remaining records into the third target.
The solution to this problem I have already posted by using aggregator and joiner. Now we will see how to implement this by reversing the contents of the file.
Solution:
Connect the source qualifier transformation to the expression transformation. In the expression transformation create the additional ports as mentioned above.
Connect the expression transformation to a router. In the router transformation create an output group and specify the group condition as o_count=1. Connect this output group to a target and the default group to sorter transformation.
Sort the data in descending order on o_count port.
Connect the output of sorter transformation to expression transformation (don’t connect o_count port).
Again in the expression transformation create the same additional ports mentioned above.
Connect this expression transformation to router and create an output group. In the output group specify the condition as o_count=1 and connect this group to second target. Connect the default group to the third group.