There are persuasive arguments for both - stored procedures are all located in a central repository, but are (potentially) hard to migrate and ad hoc queries are easier to debug as they are with your code, but they can also be harder to find in the code.
The argument that stored procedures are more efficient doesn't hold water anymore.
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Doing a google for Stored Procedure vs Dynamic Query will show decent arguments either way and probably best for you to make your own decision...
