When you set up an SQL data source and its table object, you must include each of the primary key columns in the table object. If you do not do this, you can find that two of the rows in your table appear to be the same, even though they are uniquely identified by the primary key column(s).

If you try to update one of these rows, Data Access will not be able to identify uniquely the row in the database and the update will fail. An error message from the database will be displayed indicating that if the update were to continue, more than one row would be edited. This also applies to a deletion of a row that appears to be exactly the same as another row.

If you do not want to display the primary key columns of the table in the user interface, you should change column visibility in the SQL Data Source inspector.