Constrains using fillschema or code all constraints "manual"

Hi Experts,
I use a SQL datasource to fill a datatable that I use for a VB application. When setting up the contraints in and between datatables I can use fillschema or setup all contraints (primairy keys, relations, autoincrement, etc) manual.

I have a few questions regarding this:
- Is there a preferred method? (use SQL to set all contraints and use fillschema to get the contraints).
- Should some contraints always be setup in code,  since datatable and SQL are "disconnected".
- Does one exclude the other? (use FillSchema to get contraints on the tables and setup the relations in code for instance)?
- Does someone have a good reference / link?

Regards, MBStart Free Trial