The DROP CONSTRAINT statement is part of ALTER TABLE and removes Check and Foreign Key constraints from columns.
{{site.data.alerts.callout_info}}For information about removing other constraints, see Constraints: Remove Constraints.{{site.data.alerts.end}}
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 |
+--------+---------+-------------+-----------+---------+
{{site.data.alerts.callout_info}}You cannot drop the primary constraint, which indicates your table's Primary Key.{{site.data.alerts.end}}