Seaquel
SQL Server error code

SQL Server error 6988

SQL Server raises error 6988 at severity 16, which marks a problem with the query or data that you can correct.

Invalid restriction for type '%s'. A 'choice' particle may be restricted only by 'element', 'choice', or 'sequence'.
Msg6988
Severity16
Group6000–6999

Source: Database Engine events and errors