When you define a field as a primary key in Microsoft Access, all records must have a unique entry in that field. If you attempt to enter duplicate data into the field, Access returns an error.
When using the FrontPage 2002 Server Extensions or the FrontPage 2000 Server Extensions, if you attempt to submit a form to a database with duplicate data in a field marked as a primary key, the following error message appears:
Cannot update the database.
In FrontPage 2003 and in FrontPage 2002, the following line is added to the FP_DumpError function in the Fpdbform.inc file:
This line of code is added to the file to improve cross-codepage support. It causes FrontPage to ignore the error that Access returns when a Web page attempts to add a record that contains duplicate primary key data, but it allows the confirmation page to be displayed. The operation appears successful, but Access does not allow the record that contains the duplicate primary key data to be written to the database.