| title | summary | toc |
|---|---|---|
ALTER TABLE |
Use the ALTER TABLE statement to change the schema of a table. |
false |
The ALTER TABLE statement applies a schema change to a table.
{{site.data.alerts.callout_info}}To understand how CockroachDB changes schema elements without requiring table locking or other user-visible downtime, see Online Schema Changes in CockroachDB.{{site.data.alerts.end}}
For information on using ALTER TABLE, see the documents for its relevant subcommands.
| Subcommand | Description |
|---|---|
ADD COLUMN |
Add columns to tables. |
ADD CONSTRAINT |
Add constraints to columns. |
ALTER COLUMN |
Change a column's Default constraint or drop the Not Null constraint. |
DROP COLUMN |
Remove columns from tables. |
DROP CONSTRAINT |
Remove constraints from columns. |
RENAME COLUMN |
Change the names of columns. |
RENAME TABLE |
Change the names of tables. |
SPLIT AT |
(Documentation pending) Potentially improve performance by identifying ideal locations to split data in the key-value layer. |