Seaquel
SQL Server error code

SQL Server error 1787

SQL Server raises error 1787 at severity 16, which marks a problem with the query or data that you can correct.

Cannot define foreign key constraint '%.*ls' with cascaded DELETE or UPDATE on table '%.*ls' because the table has an INSTEAD OF DELETE or UPDATE TRIGGER defined on it.
Msg1787
Severity16
Group1000–1999

Source: Database Engine events and errors