PHP Editor Review - Postgres Manual Sql-createschema

Synopsis

CREATE SCHEMA schemaname [ AUTHORIZATION username ] [ schema_element [ ... ] ]
CREATE SCHEMA AUTHORIZATION username [ schema_element [ ... ] ]

Inputs

schemaname: The name of a schema to be created. If this is omitted, the user name is used as the schema name.
username: The name of the user who will own the schema. If omitted, defaults to the user executing the command. Only superusers may create schemas owned by users other than themselves.
schema_element: An SQL statement defining an object to be created within the schema. Currently, only CREATE TABLE, CREATE VIEW, and GRANT are accepted as clauses within CREATE SCHEMA. Other kinds of objects may be created in separate commands after the schema is created.

Outputs

CREATE SCHEMA: Message returned if the command is successful.
ERROR: namespace "schemaname" already exists: If the schema specified already exists.

Description

CREATE SCHEMA will enter 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).

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.

Notes

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

Use DROP SCHEMA to remove a schema.

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 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

SQL92

SQL92 allows a DEFAULT CHARACTER SET clause in CREATE SCHEMA, as well as more subcommand types than are presently accepted by PostgreSQL.

SQL92 specifies that the subcommands in CREATE SCHEMA may appear in any order. The present PostgreSQL implementation does not handle all cases of forward references in subcommands; it may sometimes be necessary to reorder the subcommands to avoid forward references.

In SQL92, 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 CREATE rights on his schema to someone else.