CHECK constraint already exists. (Error 3756)

Applies to: Access 2013 | Access 2016

This error occurs when, using the ALTER TABLE ALTER COLUMN syntax, you try to use a constraint name for a CHECK constraint that is already used on that table. This error can also occur when using the Microsoft Access Database Engine OLE DB Provider and attempting to add a CHECK constraint that has the same name as another CHECK constraint in the same table.

See also