Wiped out the legacy compatibility option OldSetClauseSemantics in Firebird 3.0

The option in the config is removed

Prior to Firebird 2.5 the SET clause of the UPDATE statement assigned columns in the user-defined order with the NEW column values being immediately accessible to the subsequent assignments. This did not conform to the SQL standard. Starting with Firebird 2.5, only OLD column values are accessible to all the assignments of the SET clause.

Example of the old vs new behaviour:

UPDATE T SET A = B, B = A

old result: A gets equal to B, B doesn’t change

new result: A and B get their values exchanged

Change this configuration option to 1 (true) only if your SQL code relies on the legacy semantics of the SET clause. It’s provided as a temporary solution for backward compatibility issues and is removed in Firebird 3.0
Type: boolean

OldSetClauseSemantics = 0