The autovacuum daemon cannot access and therefore cannot vacuum or analyze temporary tables. For this reason, appropriate vacuum and analyze operations should be performed via session SQL commands. For example, if a temporary table is going to be used in complex queries, it is wise to run ANALYZE on the temporary table after it is populated.

Optionally, GLOBAL or LOCAL can be written before TEMPORARY or TEMP. This presently makes no difference in PostgreSQL and is deprecated; see COMPATIBILITY.

When a typed table is created, then the data types of the columns are determined by the underlying composite type and are not specified by the CREATE TABLE command. But the CREATE TABLE command can add defaults and constraints to the table and can specify storage parameters.

Use of INHERITS creates a persistent relationship between the new child table and its parent table(s). Schema modifications to the parent(s) normally propagate to children as well, and by default the data of the child table is included in scans of the parent(s).

If the same column name exists in more than one parent table, an error is reported unless the data types of the columns match in each of the parent tables. If there is no conflict, then the duplicate columns are merged to form a single column in the new table. If the column name list of the new table contains a column name that is also inherited, the data type must likewise match the inherited column(s), and the column definitions are merged into one. If the new table explicitly specifies a default value for the column, this default overrides any defaults from inherited declarations of the column. Otherwise, any parents that specify default values for the column must all specify the same default, or an error will be reported.

CHECK constraints are merged in essentially the same way as columns: if multiple parent tables and/or the new table definition contain identically-named CHECK constraints, these constraints must all have the same check expression, or an error will be reported. Constraints having the same name and expression will be merged into one copy. A constraint marked NO INHERIT in a parent will not be considered. Notice that an unnamed CHECK constraint in the new table will never be merged, since a unique name will always be chosen for it.

Column STORAGE settings are also copied from parent tables.

Unlike INHERITS, the new table and original table are completely decoupled after creation is complete. Changes to the original table will not be applied to the new table, and it is not possible to include data of the new table in scans of the original table.

Default expressions for the copied column definitions will be copied only if INCLUDING DEFAULTS is specified. The default behavior is to exclude default expressions, resulting in the copied columns in the new table having null defaults. Note that copying defaults that call database-modification functions, such as nextval, may create a functional linkage between the original and new tables.

Not-null constraints are always copied to the new table. CHECK constraints will be copied only if INCLUDING CONSTRAINTS is specified. No distinction is made between column constraints and table constraints.

Indexes, PRIMARY KEY, UNIQUE, and EXCLUDE constraints on the original table will be created on the new table only if INCLUDING INDEXES is specified. Names for the new indexes and constraints are chosen according to the default rules, regardless of how the originals were named. (This behavior avoids possible duplicate-name failures for the new indexes.)

STORAGE settings for the copied column definitions will be copied only if INCLUDING STORAGE is specified. The default behavior is to exclude STORAGE settings, resulting in the copied columns in the new table having type-specific default settings. For more on STORAGE settings, see Section 56.2, “TOAST”, in the documentation.

Comments for the copied columns, constraints, and indexes will be copied only if INCLUDING COMMENTS is specified. The default behavior is to exclude comments, resulting in the copied columns and constraints in the new table having no comments.

INCLUDING ALL is an abbreviated form of INCLUDING DEFAULTS INCLUDING CONSTRAINTS INCLUDING INDEXES INCLUDING STORAGE INCLUDING COMMENTS.

Note that unlike INHERITS, columns and constraints copied by LIKE are not merged with similarly named columns and constraints. If the same name is specified explicitly or in another LIKE clause, an error is signaled.

The LIKE clause can also be used to copy column definitions from views, foreign tables, or composite types. Inapplicable options (e.g., INCLUDING INDEXES from a view) are ignored.

This clause is only provided for compatibility with non-standard SQL databases. Its use is discouraged in new applications.

Currently, CHECK expressions cannot contain subqueries nor refer to variables other than columns of the current row.

A constraint marked with NO INHERIT will not propagate to child tables.

The default expression will be used in any insert operation that does not specify a value for the column. If there is no default for a column, then the default is null.

For the purpose of a unique constraint, null values are not considered equal.

Each unique table constraint must name a set of columns that is different from the set of columns named by any other unique or primary key constraint defined for the table. (Otherwise it would just be the same constraint listed twice.)

The primary key constraint should name a set of columns that is different from the set of columns named by any unique constraint defined for the same table. (Otherwise, the unique constraint is redundant and will be discarded.)

PRIMARY KEY enforces the same data constraints as a combination of UNIQUE and NOT NULL, but identifying a set of columns as the primary key also provides metadata about the design of the schema, since a primary key implies that other tables can rely on this set of columns as a unique identifier for rows.

Exclusion constraints are implemented using an index, so each specified operator must be associated with an appropriate operator class (see Section 11.9, “Operator Classes and Operator Families”, in the documentation) for the index access method index_method. The operators are required to be commutative. Each exclude_element can optionally specify an operator class and/or ordering options; these are described fully under CREATE INDEX (CREATE_INDEX(7)).

The access method must support amgettuple (see Chapter 52, Index Access Method Interface Definition, in the documentation); at present this means GIN cannot be used. Although it's allowed, there is little point in using B-tree or hash indexes with an exclusion constraint, because this does nothing that an ordinary unique constraint doesn't do better. So in practice the access method will always be GiST or SP-GiST.

The predicate allows you to specify an exclusion constraint on a subset of the table; internally this creates a partial index. Note that parentheses are required around the predicate.

A value inserted into the referencing column(s) is matched against the values of the referenced table and referenced columns using the given match type. There are three match types: MATCH FULL, MATCH PARTIAL, and MATCH SIMPLE, which is also the default. MATCH FULL will not allow one column of a multicolumn foreign key to be null unless all foreign key columns are null. MATCH SIMPLE allows some foreign key columns to be null while other parts of the foreign key are not null. MATCH PARTIAL is not yet implemented.

In addition, when the data in the referenced columns is changed, certain actions are performed on the data in this table's columns. The ON DELETE clause specifies the action to perform when a referenced row in the referenced table is being deleted. Likewise, the ON UPDATE clause specifies the action to perform when a referenced column in the referenced table is being updated to a new value. If the row is updated, but the referenced column is not actually changed, no action is done. Referential actions other than the NO ACTION check cannot be deferred, even if the constraint is declared deferrable. There are the following possible actions for each clause:

NO ACTION

RESTRICT

CASCADE

SET NULL

SET DEFAULT

If the referenced column(s) are changed frequently, it might be wise to add an index to the foreign key column so that referential actions associated with the foreign key column can be performed more efficiently.

If OIDS=FALSE is specified or implied, the new table does not store OIDs and no OID will be assigned for a row inserted into it. This is generally considered worthwhile, since it will reduce OID consumption and thereby postpone the wraparound of the 32-bit OID counter. Once the counter wraps around, OIDs can no longer be assumed to be unique, which makes them considerably less useful. In addition, excluding OIDs from a table reduces the space required to store the table on disk by 4 bytes per row (on most machines), slightly improving performance.

To remove OIDs from a table after it has been created, use ALTER TABLE (ALTER_TABLE(7)).

PRESERVE ROWS

DELETE ROWS

DROP

The use of OIDS=FALSE is not recommended for tables with no primary key, since without either an OID or a unique data key, it is difficult to identify specific rows.

CREATE TABLE films (


    code        char(5) CONSTRAINT firstkey PRIMARY KEY,


    title       varchar(40) NOT NULL,


    did         integer NOT NULL,


    date_prod   date,


    kind        varchar(10),


    len         interval hour to minute
);
CREATE TABLE distributors (


     did    integer PRIMARY KEY DEFAULT nextval('serial'),


     name   varchar(40) NOT NULL CHECK (name <> '')
);

CREATE TABLE array_int (


    vector  int[][]
);

CREATE TABLE films (


    code        char(5),


    title       varchar(40),


    did         integer,


    date_prod   date,


    kind        varchar(10),


    len         interval hour to minute,


    CONSTRAINT production UNIQUE(date_prod)
);

CREATE TABLE distributors (


    did     integer CHECK (did > 100),


    name    varchar(40)
);

CREATE TABLE distributors (


    did     integer,


    name    varchar(40)


    CONSTRAINT con1 CHECK (did > 100 AND name <> '')
);

CREATE TABLE films (


    code        char(5),


    title       varchar(40),


    did         integer,


    date_prod   date,


    kind        varchar(10),


    len         interval hour to minute,


    CONSTRAINT code_title PRIMARY KEY(code,title)
);

CREATE TABLE distributors (


    did     integer,


    name    varchar(40),


    PRIMARY KEY(did)
);
CREATE TABLE distributors (


    did     integer PRIMARY KEY,


    name    varchar(40)
);

CREATE TABLE distributors (


    name      varchar(40) DEFAULT 'Luso Films',


    did       integer DEFAULT nextval('distributors_serial'),


    modtime   timestamp DEFAULT current_timestamp
);

CREATE TABLE distributors (


    did     integer CONSTRAINT no_null NOT NULL,


    name    varchar(40) NOT NULL
);

CREATE TABLE distributors (


    did     integer,


    name    varchar(40) UNIQUE
);

CREATE TABLE distributors (


    did     integer,


    name    varchar(40),


    UNIQUE(name)
);

CREATE TABLE distributors (


    did     integer,


    name    varchar(40),


    UNIQUE(name) WITH (fillfactor=70)
)
WITH (fillfactor=70);

CREATE TABLE circles (


    c circle,


    EXCLUDE USING gist (c WITH &&)
);

CREATE TABLE cinemas (


        id serial,


        name text,


        location text
) TABLESPACE diskvol1;

CREATE TYPE employee_type AS (name text, salary numeric);
CREATE TABLE employees OF employee_type (


    PRIMARY KEY (name),


    salary WITH OPTIONS DEFAULT 1000
);