CREATE SCHEMA

CREATE SCHEMA

7

SQL - Language Statements

CREATE SCHEMA

define a new schema

CREATE SCHEMA

schema\_name

\[ AUTHORIZATION

role\_specification

\] \[

schema\_element

\[ \... \] \] CREATE SCHEMA AUTHORIZATION

role\_specification

\[

schema\_element

\[ \... \] \] CREATE SCHEMA IF NOT EXISTS

schema\_name

\[ AUTHORIZATION

role\_specification

\] CREATE SCHEMA IF NOT EXISTS AUTHORIZATION

role\_specification

where

role\_specification

can be:

user\_name

\| CURRENT\_ROLE \| CURRENT\_USER \| SESSION\_USER

Description
===========

`CREATE SCHEMA` enters a new schema into the current database. The
schema name must be distinct from the name of any existing schema in the
current database.

A schema is essentially a namespace: it contains named objects (tables,
data types, functions, and operators) whose names can duplicate those of
other objects existing in other schemas. Named objects are accessed
either by "qualifying" their names with the schema name as a prefix, or
by setting a search path that includes the desired schema(s). A `CREATE`
command specifying an unqualified object name creates the object in the
current schema (the one at the front of the search path, which can be
determined with the function `current_schema`).

Optionally, `CREATE SCHEMA` can include subcommands to create objects
within the new schema. The subcommands are treated essentially the same
as separate commands issued after creating the schema, except that if
the `AUTHORIZATION` clause is used, all the created objects will be
owned by that user.

Parameters
==========

schema\_name

:   The name of a schema to be created. If this is omitted, the
    user\_name is used as the schema name. The name cannot begin with
    `pg_`, as such names are reserved for system schemas.

user\_name

:   The role name of the user who will own the new schema. If omitted,
    defaults to the user executing the command. To create a schema owned
    by another role, you must be a direct or indirect member of that
    role, or be a superuser.

schema\_element

:   An SQL statement defining an object to be created within the schema.
    Currently, only `CREATE
            TABLE`, `CREATE VIEW`, `CREATE
            INDEX`, `CREATE SEQUENCE`, `CREATE
            TRIGGER` and `GRANT` are accepted as clauses within
    `CREATE SCHEMA`. Other kinds of objects may be created in separate
    commands after the schema is created.

`IF NOT EXISTS`

:   Do nothing (except issuing a notice) if a schema with the same name
    already exists. schema\_element subcommands cannot be included when
    this option is used.

Notes
=====

To create a schema, the invoking user must have the `CREATE` privilege
for the current database. (Of course, superusers bypass this check.)

Examples
========

Create a schema:

    CREATE SCHEMA myschema;

Create a schema for user `joe`; the schema will also be named `joe`:

    CREATE SCHEMA AUTHORIZATION joe;

Create a schema named `test` that will be owned by user `joe`, unless
there already is a schema named `test`. (It does not matter whether
`joe` owns the pre-existing schema.)

    CREATE SCHEMA IF NOT EXISTS test AUTHORIZATION joe;

Create a schema and create a table and view within it:

    CREATE SCHEMA hollywood
        CREATE TABLE films (title text, release date, awards text[])
        CREATE VIEW winners AS
            SELECT title, release FROM films WHERE awards IS NOT NULL;

Notice that the individual subcommands do not end with semicolons.

The following is an equivalent way of accomplishing the same result:

    CREATE SCHEMA hollywood;
    CREATE TABLE hollywood.films (title text, release date, awards text[]);
    CREATE VIEW hollywood.winners AS
        SELECT title, release FROM hollywood.films WHERE awards IS NOT NULL;

Compatibility
=============

The SQL standard allows a `DEFAULT CHARACTER SET` clause in
`CREATE SCHEMA`, as well as more subcommand types than are presently
accepted by PostgreSQL.

The SQL standard specifies that the subcommands in `CREATE
   SCHEMA` can appear in any order. The present PostgreSQL
implementation does not handle all cases of forward references in
subcommands; it might sometimes be necessary to reorder the subcommands
in order to avoid forward references.

According to the SQL standard, the owner of a schema always owns all
objects within it. PostgreSQL allows schemas to contain objects owned by
users other than the schema owner. This can happen only if the schema
owner grants the `CREATE` privilege on their schema to someone else, or
a superuser chooses to create objects in it.

The `IF NOT EXISTS` option is a PostgreSQL extension.

See Also
========
