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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. |
Viewing Schema Changes
Whenever you initiate a schema change, CockroachDB registers it as a job, which you can view with SHOW JOBS.
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 | +--------+---------+-------------+-----------+---------+