The CREATE SCHEMA statement creates a user-defined schema.
You can also create a user-defined schema by converting an existing database to a schema using ALTER DATABASE ... CONVERT TO SCHEMA.
Required privileges
- Only members of the
adminrole can create new schemas. By default, therootuser belongs to theadminrole. - To grant privileges on a user-defined schema, a user must have the
GRANTprivilege on the schema and the privilege that they want to grant. - To create or interact with objects that depend on a user-defined schema, a user must have the
USAGEprivilege on the schema.
Syntax
Parameters
| Parameter | Description |
|---|---|
IF NOT EXISTS |
Create a new schema only if a schema of the same name does not already exist within the database. If one does exist, do not return an error. |
namename.name |
The name of the schema to create, or the name of the database in which to create the schema and the schema name, separated by a ".". The schema name must be unique within its database and follow these identifier rules. |
AUTHORIZATION role_spec |
Optionally identify a user (role_spec) to be the owner of the schema.If a CREATE SCHEMA statement has an AUTHORIZATION clause, but no schema name is specified, the schema will be named after the specified owner of the schema. If a CREATE SCHEMA statement does not have an AUTHORIZATION clause, the user executing the statement will be named the owner. |
Example
Setup
The following examples use MovR, a fictional vehicle-sharing application, to demonstrate CockroachDB SQL statements. For more information about the MovR example application and dataset, see MovR: A Global Vehicle-sharing App.
To follow along, run cockroach demo to start a temporary, in-memory cluster with the movr dataset preloaded:
$ cockroach demo
Create a schema
> CREATE SCHEMA org_one;
> SHOW SCHEMAS;
schema_name
----------------------
crdb_internal
information_schema
org_one
pg_catalog
pg_extension
public
(6 rows)
By default, the user executing the CREATE SCHEMA statement is the owner of the schema. For example, suppose you created the schema as user root. root would be the owner of the schema.
Create a schema if one does not exist
> CREATE SCHEMA org_one;
ERROR: schema "org_one" already exists
> CREATE SCHEMA IF NOT EXISTS org_one;
SQL does not generate an error, even though a new schema wasn't created.
> SHOW SCHEMAS;
schema_name
----------------------
crdb_internal
information_schema
org_one
pg_catalog
pg_extension
public
(6 rows)
Create two tables of the same name in different schemas
You can create tables of the same name in the same database if they are in separate schemas.
> CREATE SCHEMA IF NOT EXISTS org_one;
> CREATE SCHEMA IF NOT EXISTS org_two;
> SHOW SCHEMAS;
schema_name
----------------------
crdb_internal
information_schema
org_one
org_two
pg_catalog
pg_extension
public
(7 rows)
> CREATE TABLE org_one.employees (
id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
name STRING,
desk_no INT UNIQUE
);
> CREATE TABLE org_two.employees (
id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
name STRING,
desk_no INT UNIQUE
);
> SELECT * FROM [SHOW TABLES] WHERE table_name='employees';
schema_name | table_name | type | estimated_row_count
--------------+------------+-------+----------------------
org_one | employees | table | 0
org_two | employees | table | 0
(2 rows)
Create a schema with authorization
To specify the owner of a schema, add an AUTHORIZATION clause to the CREATE SCHEMA statement:
> CREATE USER max WITH PASSWORD 'roach';
> CREATE SCHEMA org_two AUTHORIZATION max;
> SHOW SCHEMAS;
schema_name
----------------------
crdb_internal
information_schema
org_two
pg_catalog
pg_extension
public
(6 rows)
If no schema name is specified in a CREATE SCHEMA statement with an AUTHORIZATION clause, the schema will be named after the user specified:
> CREATE SCHEMA AUTHORIZATION max;
> SHOW SCHEMAS;
schema_name
----------------------
crdb_internal
information_schema
max
org_two
pg_catalog
pg_extension
public
(7 rows)
When you use a table without specifying a schema, CockroachDB looks for the table in the $user schema (i.e., a schema named after the current user). If no schema exists with the name of the current user, the public schema is used.
For example, suppose that you grant the root role (i.e., the role of the current user root) to the max user:
> GRANT root TO max;
Then, max accesses the cluster and creates two tables of the same name, in the same database, one in the max schema, and one in the public schema:
$ cockroach sql --url 'postgres://max:roach@host:port/db?sslmode=require'
> CREATE TABLE max.accounts (
id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
name STRING,
balance DECIMAL
);
> CREATE TABLE public.accounts (
id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
name STRING,
balance DECIMAL
);
> SHOW TABLES;
schema_name | table_name | type | estimated_row_count
--------------+------------+-------+----------------------
max | accounts | table | 0
public | accounts | table | 0
(2 rows)
max then inserts some values into the accounts table, without specifying a schema:
> INSERT INTO accounts (name, balance) VALUES ('checking', 1000), ('savings', 15000);
> SELECT * FROM accounts;
id | name | balance
---------------------------------------+----------+----------
7610607e-4928-44fb-9f4e-7ae6d6520666 | savings | 15000
860b7891-cde4-4aff-a318-f928d47374bc | checking | 1000
(2 rows)
Because max is the current user, all unqualified accounts table names resolve as max.accounts, and not public.accounts.
> SELECT * FROM public.accounts;
id | name | balance
-----+------+----------
(0 rows)
See also
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