3404
MySQLERRORNotableForeign KeysHIGH confidence
Cannot find column in foreign key cache
Production Risk
Medium — DDL fails; existing foreign key constraints may be affected.
How to reproduce
trigger — this will error
trigger — this will error
ALTER TABLE child ADD FOREIGN KEY (fk_col) REFERENCES parent(nonexistent_col);
expected output
ERROR 3404 (HY000): Cannot find column in foreign key cache.
Fix
Verify column existence and refresh metadata
Verify column existence and refresh metadata
DESCRIBE parent; ANALYZE TABLE parent;
Why this works
DESCRIBE confirms the column name and ANALYZE TABLE refreshes the metadata cache.
What not to do
✕
Sources
Official documentation ↗
MySQL 8.0 — 3404 ER_CANNOT_FIND_COLUMN_IN_FOREIGN_KEY_CACHE
Content generated with AI assistance and reviewed for accuracy. Found an error? hello@errcodes.dev