Wednesday, November 3, 2010

Avoiding Meta data Callbacks due to Hard-Coded SQLs

You would probably have noticed that Cognos creates meta data call-backs when you have reports based on Query Subjects that have SQLs hard-coded in them. To avoid such call-backs, import all the tables referenced by your query and leave them untouched. Cognos will reference the meta data from these tables while generating the SQL hard-coded in the query subject.

I would suggest it best to avoid hard-coding SQLs in query subjects but instead to create them as views in the DB and reference them through Cognos. This would help ensure better maintenance of objects and in easier impact-analysis of DB changes. Hard-Coded SQLs in query subjects should only be used when dynamicity is required through the usage of Cognos macros in the queries.

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