EC
4025
MariaDBERRORCommonData IntegrityHIGH confidence

CONSTRAINT check failed

What this means

ER_CONSTRAINT_FAILED (4025) is returned when a CHECK constraint on a table is violated during INSERT or UPDATE. MariaDB enforces CHECK constraints from version 10.2.1+.

How to reproduce
trigger — this will error
trigger — this will error
CREATE TABLE products (
  id   INT PRIMARY KEY,
  price DECIMAL(10,2),
  CONSTRAINT chk_price CHECK (price >= 0)
);
INSERT INTO products VALUES (1, -5.00);

expected output

ERROR 4025 (23000): CONSTRAINT `chk_price` failed for `mydb`.`products`

Fix 1

Validate the value before inserting

WHEN The application controls the value.

Validate the value before inserting
-- Application: validate price >= 0 before insert
-- SQL: show all constraints on a table:
SELECT CONSTRAINT_NAME, CHECK_CLAUSE
FROM INFORMATION_SCHEMA.CHECK_CONSTRAINTS
WHERE TABLE_NAME = 'products';

Why this works

INFORMATION_SCHEMA.CHECK_CONSTRAINTS documents all CHECK constraints so applications can mirror the validation logic.

Fix 2

Update or drop the constraint

WHEN The constraint definition is wrong.

Update or drop the constraint
-- MariaDB 10.2+: drop and recreate
ALTER TABLE products DROP CONSTRAINT chk_price;
ALTER TABLE products ADD CONSTRAINT chk_price CHECK (price >= -100);

Why this works

ALTER TABLE can drop and re-add CHECK constraints without rebuilding the entire table in modern MariaDB.

What not to do

✕ Drop CHECK constraints to suppress validation errors

CHECK constraints are the last line of defence against invalid data in the database layer; application-level validation is not sufficient on its own.

Version notes
MariaDB 10.2.1

CHECK constraints became enforced in MariaDB 10.2.1. Earlier versions accepted the syntax but did not enforce the constraint.

Sources
Official documentation ↗

MariaDB — CHECK Constraints

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