MariaDB [test]> create table t (
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-> a int,
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-> b int,
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->
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-> constraint x unique (a),
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-> constraint y check (b = 1)
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-> );
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Query OK, 0 rows affected (0.00 sec)
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MariaDB [test]> INSERT INTO t VALUES(1,1);
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Query OK, 1 row affected (0.00 sec)
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MariaDB [test]> INSERT INTO t VALUES(1,2);
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ERROR 4025 (23000): CONSTRAINT `y` failed for `test`.`t`
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MariaDB [test]> INSERT INTO t VALUES(2,1);
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Query OK, 1 row affected (0.00 sec)
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MariaDB [test]> INSERT INTO t VALUES(2,1);
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ERROR 1062 (23000): Duplicate entry '2' for key 'x'
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MariaDB [test]> ALTER TABLE t DROP CONSTRAINT x;
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Query OK, 2 rows affected (0.01 sec)
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Records: 2 Duplicates: 0 Warnings: 0
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MariaDB [test]> INSERT INTO t VALUES(2,1);
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Query OK, 1 row affected (0.00 sec)
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MariaDB [test]> SELECT * FROM t;
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+------+------+
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| a | b |
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+------+------+
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| 1 | 1 |
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| 2 | 1 |
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| 2 | 1 |
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+------+------+
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3 rows in set (0.00 sec)
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