Order of execution in mapping

[bsellick]

I have the following situation in mapping (Informatica v6):

Source -> SQ -> Expression -> Target

Source -> SQ -> Expression -> Target

Source -> SQ -> Expression -> Target

Source -> SQ -> Expression -> Target

Each source is different but the target is the same table (just renamed logically each time).

The first question I have is: when this mapping is run, does each stream run sequentially starting at the first stream listed and working down or do all streams run simultaneously?

Based on the answer for above - if I checked on the "target truncate" field for stream #1, can I be sure that I'll always truncate the target before records are inserted from other streams?

 

[rasETL]

bsellick

I am fairly new to Informatica, so bear with me.

I believe the "Target Truncate" option is set in a Workflow, not a Mapping. Therefore, it doesn't matter what order the Mapping is executed.

 

[bsellick]

Oh, yes. Sorry.

That option is turned on in the session object.

However, it has only been turned on for the first target table - the one in the very first processing stream shown in the mapping (which may have a logical name of TABLE1 but the underlying physical table name would be the same for all targets).

 

[rasETL]

OK

I'm pretty sure the target table will be truncated by the Workflow before any of the Mapping ("the session")is executed.

 

[pbackstrom]

Also you can use Target Load Order in the mapping - Mappings Target Load Plan if you want to control not having them sequential within the mapping. It goes by source qualifier.

 

[kavin]

yes pbackstrom is correct. You can define you own sequence in mapping (in Informatica Designer) using Mapping --> Target Load option. Here you can set the sequence.

While Truncate target will work only once at starting of the work flow. So dont worry about that. It will not truncate everytime.

 

[blom0344]

Generally speaking, INFA good practice is NOT to create mappings with unrelated dataflows. Create a mapping for each dataflow and sessions on each mapping.
This will allow you maximum control if you put them sequentially in a workflow...

Ties Blom
Information analyst