CREATE SCHEMA
CREATE SCHEMA — define a new schema
Synopsis
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 withpg_
, 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
andGRANT
are accepted as clauses withinCREATE 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;
Compatibility
The SQL standard allows a DEFAULT CHARACTER SET
clause in CREATE SCHEMA
, as well as more subcommand types than are presently accepted by ProtonBase.
The SQL standard specifies that the subcommands in CREATE SCHEMA
can appear in any order. The present ProtonBase 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. ProtonBase 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 ProtonBase extension.