3609
MySQLWARNINGCriticalDDLHIGH confidence
Redundant constraint ignored
Production Risk
Low — Warning only; the DDL operation succeeds.
How to reproduce
trigger — this will error
trigger — this will error
CREATE TABLE t (id INT NOT NULL PRIMARY KEY);
expected output
Warning 3609: Redundant constraint 'NOT NULL' ignored.
Fix
Simplify column definition
Simplify column definition
CREATE TABLE t (id INT PRIMARY KEY);
Why this works
PRIMARY KEY already implies NOT NULL; explicit NOT NULL is redundant.
What not to do
✕
Version notes
Sources
Official documentation ↗
MySQL 8.0 — 3609 ER_WARN_REDUNDANT_CONSTRAINT
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