Firebird psql updating comparing online and traditional dating
A trigger is a self-contained PSQL routine associated with a table or view that automatically performs an action when a row in the table or view is inserted, updated, or deleted.
clause; columns not explicitly modified retain their previous values.
SQL roles are not supported in on older versions of the database.
The attempted to read or write a value that was not stored on a memory boundary.
If it does, then only one of the join rows will be used to update the target row, but which one will be used is not readily predictable.
Because of this indeterminacy, referencing other tables only within sub-selects is safer, though often harder to read and slower than using a join.
The clause, if present, need not contain all the modified columns and may also contain other columns or expressions.