Defines 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_USER | SESSION_USER
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 may 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
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 role.
pg_, as such names are reserved for system catalog schemas.
CREATE TRIGGER, and
GRANTare accepted as clauses within
CREATE SCHEMA. Other kinds of objects may be created in separate commands after the schema is created.
Greenplum Database does not support triggers.
IF NOT EXISTS
To create a schema, the invoking user must have the
CREATE privilege for the current database or be a superuser.
Create a schema:
CREATE SCHEMA myschema;
Create a schema for role
joe; the schema will also be named
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;
The SQL standard allows a
DEFAULT CHARACTER SET clause in
CREATE SCHEMA, as well as more subcommand types than are presently accepted by Greenplum Database.
The SQL standard specifies that the subcommands in
CREATE SCHEMA may appear in any order. The present Greenplum Database implementation does not handle all cases of forward references in subcommands; it may 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. Greenplum Database 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 the schema to someone else, or a superuser chooses to create objects in it.
IF NOT EXISTS option is a Greenplum Database extension.
Parent topic: SQL Commands