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The DROP CONSTRAINT statement is part of ALTER TABLE and removes Check and Foreign Key constraints from columns.
Note:
For information about removing other constraints, see Constraints: Remove Constraints.Synopsis
Required Privileges
The user must have the CREATE privilege on the table.
Parameters
| Parameter | Description |
|---|---|
table_name |
The name of the table with the constraint you want to drop. |
name |
The name of the constraint you want to drop. |
Example
> SHOW CONSTRAINTS FROM orders;
+--------+---------------------------+-------------+-----------+----------------+
| Table | Name | Type | Column(s) | Details |
+--------+---------------------------+-------------+-----------+----------------+
| orders | fk_customer_ref_customers | FOREIGN KEY | customer | customers.[id] |
| orders | primary | PRIMARY KEY | id | NULL |
+--------+---------------------------+-------------+-----------+----------------+
> ALTER TABLE orders DROP CONSTRAINT fk_customer_ref_customers;
ALTER TABLE
> SHOW CONSTRAINTS FROM orders;
+--------+---------+-------------+-----------+---------+
| Table | Name | Type | Column(s) | Details |
+--------+---------+-------------+-----------+---------+
| orders | primary | PRIMARY KEY | id | NULL |
+--------+---------+-------------+-----------+---------+
See Also
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