Let's assume you want to just get back n number of rows. If you are using SDE, you could use ArcSDESQLExecute's methods to perform your sql, but you could also use a sub-query.
Take your default statement that ArcMap allows you to perform on a layer:
"Select * from wgs.temp where "
Since we want to just get back n number of rows, use the OBJECTID field as a reference and the 'in' function:
"Select * from wgs.temp where OBJECT in (select OBJECTID from wgs.temp where rownum <= 5)"
This will return 5 rows in the data set. If you want 10, 15, of n number of rows, replace the 5 with whatever value you want. You can apply this to update and search cursors on SDE data only.