datagrid edit

Hi,
When trying to edit rows in the datagrid does the underlying datasource need to have a single primary key - i.e. can editing be set up on a source which has composite key?
If it can - how?

Cheers.

Its easier if you have a primary key. If not, you'll have to build a sql statement to check for all the fields.

Thanks,
the reason I'm asking is that my app doesn't respond to edit button - not firing Datagrid_EditCommand at all.
The datagrid is based on a dataview which has filtered on the foreign key and currently there is no unique key for this table.