Seaquel
SQL Server error code

SQL Server error 4444

SQL Server raises error 4444 at severity 16, which marks a problem with the query or data that you can correct.

UNION ALL view '%.*ls' is not updatable because the primary key of table '%.*ls' is not included in the union result.
Msg4444
Severity16
Group4000–4999

Source: Database Engine events and errors