[icedchai]

I think the data mapping part is pretty important: a programmatic way to map from SQL result sets to objects. That stuff is incredibly tedious (and error prone) when you do it manually.

[pgt]

Decomposing the result set is much simpler if the caller composed the query. Harder if you have to parse SQL to know what to expect back.

[icedchai]

It depends. I've written a few half baked object mappers and never needed to parse SQL, since I've always used metadata from the result set (column names, data types, etc.)