Yes, this examples help you a lot. http://blogs.conchango.com/jamiethomson/archive/2006/09/12/SSIS_3A00_-Checking-if-a-row-exists-and-if-it-does_2C00_-has-it-changed.aspx

I think if you use the Lookup transformation it will help you. The Lookup transformation performs lookups by joining data in input columns with columns in a reference dataset.