The ALTER VIEW statement applies a schema change to a view.
The ALTER VIEW statement performs a schema change. For more information about how online schema changes work in CockroachDB, see Online Schema Changes.
Required privileges
- To alter a view, the user must have the
CREATEprivilege on the parent database. - To change the schema of a view with
ALTER VIEW ... SET SCHEMA, or to change the name of a view withALTER VIEW ... RENAME TO, the user must also have theDROPprivilege on the view.
Syntax
Parameters
| Parameter | Description |
|---|---|
MATERIALIZED |
Rename a materialized view. |
IF EXISTS |
Rename the view only if a view of view_name exists; if one does not exist, do not return an error. |
view_name |
The name of the view to rename. To find existing view names, use:SELECT * FROM information_schema.tables WHERE table_type = 'VIEW'; |
view_new_name |
The new name of the view. The name of the view must be unique to its database and follow these identifier rules. Name changes do not propagate to the table(s) using the view. |
schema_name |
The name of the new schema. |
role_spec |
The role to set as the owner of the view. |
Limitations
CockroachDB does not currently support:
- Changing the
SELECTstatement executed by a view. Instead, you must drop the existing view and create a new view. - Renaming a view that other views depend on. This feature may be added in the future (see tracking issue).
Examples
Rename a view
Suppose you create a new view that you want to rename:
CREATE VIEW money_rides (id, revenue) AS SELECT id, revenue FROM rides WHERE revenue > 50;
WITH x AS (SHOW TABLES) SELECT * FROM x WHERE type = 'view';
schema_name | table_name | type | owner | estimated_row_count | locality
--------------+-------------+------+-------+---------------------+-----------
public | money_rides | view | demo | 0 | NULL
(1 row)
ALTER VIEW money_rides RENAME TO expensive_rides;
RENAME VIEW
WITH x AS (SHOW TABLES) SELECT * FROM x WHERE type = 'view';
schema_name | table_name | type | owner | estimated_row_count | locality
--------------+-----------------+------+-------+---------------------+-----------
public | expensive_rides | view | demo | 0 | NULL
(1 row)
Note that RENAME TO can be used to move a view from one database to another, but it cannot be used to move a view from one schema to another. To change a view's schema, use the SET SCHEMA clause. In a future release, RENAME TO will be limited to changing the name of a view, and will not have the ability to change a view's database.
Change the schema of a view
Suppose you want to add the expensive_rides view to a schema called cockroach_labs:
By default, unqualified views created in the database belong to the public schema:
SHOW CREATE public.expensive_rides;
table_name | create_statement
-------------------------+-------------------------------------------------------------------------------------------------------------------
public.expensive_rides | CREATE VIEW public.expensive_rides (id, revenue) AS SELECT id, revenue FROM movr.public.rides WHERE revenue > 50
(1 row)
If the new schema does not already exist, create it:
CREATE SCHEMA IF NOT EXISTS cockroach_labs;
Then, change the view's schema:
ALTER VIEW expensive_rides SET SCHEMA cockroach_labs;
SHOW CREATE public.expensive_rides;
ERROR: relation "public.expensive_rides" does not exist
SQLSTATE: 42P01
SHOW CREATE cockroach_labs.expensive_rides;
table_name | create_statement
---------------------------------+---------------------------------------------------------------------------------------------------------------------------
cockroach_labs.expensive_rides | CREATE VIEW cockroach_labs.expensive_rides (id, revenue) AS SELECT id, revenue FROM movr.public.rides WHERE revenue > 50
(1 row)
See also
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