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CREATE TABLE()			 SQL Commands			CREATE TABLE()



NAME
       CREATE TABLE - define a new table


SYNOPSIS
       CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } ] TABLE table_name ( [
	 { column_name data_type [ DEFAULT default_expr ] [ column_constraint [ ... ] ]
	   | table_constraint
	   | LIKE parent_table [ { INCLUDING | EXCLUDING } DEFAULTS ] }
	   [, ... ]
       ] )
       [ INHERITS ( parent_table [, ... ] ) ]
       [ WITH OIDS | WITHOUT OIDS ]
       [ ON COMMIT { PRESERVE ROWS | DELETE ROWS | DROP } ]
       [ TABLESPACE tablespace ]

       where column_constraint is:

       [ CONSTRAINT constraint_name ]
       { NOT NULL |
	 NULL |
	 UNIQUE [ USING INDEX TABLESPACE tablespace ] |
	 PRIMARY KEY [ USING INDEX TABLESPACE tablespace ] |
	 CHECK (expression) |
	 REFERENCES reftable [ ( refcolumn ) ] [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ]
	   [ ON DELETE action ] [ ON UPDATE action ] }
       [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]

       and table_constraint is:

       [ CONSTRAINT constraint_name ]
       { UNIQUE ( column_name [, ... ] ) [ USING INDEX TABLESPACE tablespace ] |
	 PRIMARY KEY ( column_name [, ... ] ) [ USING INDEX TABLESPACE tablespace ] |
	 CHECK ( expression ) |
	 FOREIGN KEY ( column_name [, ... ] ) REFERENCES reftable [ ( refcolumn [, ... ] ) ]
	   [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ] [ ON DELETE action ] [ ON UPDATE action ] }
       [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]


DESCRIPTION
       CREATE  TABLE  will  create a new, initially empty table in the current
       database. The table will be owned by the user issuing the command.

       If a schema name is given (for example, CREATE  TABLE  myschema.mytable
       ...) then the table is created in the specified schema. Otherwise it is
       created in the current schema. Temporary	 tables	 exist	in  a  special
       schema, so a schema name may not be given when creating a temporary ta-
       ble. The name of the table must be distinct from the name of any	 other
       table, sequence, index, or view in the same schema.

       CREATE TABLE also automatically creates a data type that represents the
       composite type corresponding to one row of the table. Therefore, tables
       cannot have the same name as any existing data type in the same schema.

       The optional constraint clauses specify constraints (tests) that new or
       updated rows must satisfy for an insert or update operation to succeed.
       A constraint is an SQL object that helps define the set of valid values
       in the table in various ways.

       There  are two ways to define constraints: table constraints and column
       constraints. A column constraint is defined as part of a column defini-
       tion. A table constraint definition is not tied to a particular column,
       and it can encompass more than one column.  Every column constraint can
       also  be	 written  as a table constraint; a column constraint is only a
       notational convenience for use when the	constraint  only  affects  one
       column.

PARAMETERS
       TEMPORARY or TEMP
	      If specified, the table is created as a temporary table.	Tempo-
	      rary tables are automatically dropped at the end of  a  session,
	      or optionally at the end of the current transaction (see ON COM-
	      MIT below). Existing permanent tables with the same name are not
	      visible to the current session while the temporary table exists,
	      unless they are  referenced  with	 schema-qualified  names.  Any
	      indexes created on a temporary table are automatically temporary
	      as well.

	      Optionally, GLOBAL or LOCAL can be written before	 TEMPORARY  or
	      TEMP.   This makes no difference in PostgreSQL, but see Compati-
	      bility [create_table(7)].

       table_name
	      The name (optionally schema-qualified) of the table to  be  cre-
	      ated.

       column_name
	      The name of a column to be created in the new table.

       data_type
	      The  data type of the column. This may include array specifiers.
	      For more information on the data types supported by  PostgreSQL,
	      refer to the documentation.

       DEFAULT
	      The  DEFAULT  clause assigns a default data value for the column
	      whose column definition it appears  within.  The	value  is  any
	      variable-free  expression	 (subqueries  and  cross-references to
	      other columns in the current table are not  allowed).  The  data
	      type  of	the default expression must match the data type of the
	      column.

	      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.

       INHERITS ( parent_table [, ... ] )
	      The optional INHERITS clause specifies a	list  of  tables  from
	      which the new table automatically inherits all columns.

	      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 col-
	      umn name that is also inherited, the  data  type	must  likewise
	      match  the  inherited  column(s), and the column definitions are
	      merged into one. However, inherited and new column  declarations
	      of  the  same  name  need not specify identical constraints: all
	      constraints provided from any declaration	 are  merged  together
	      and  all	are applied to the new table. If the new table explic-
	      itly specifies a default value  for  the	column,	 this  default
	      overrides	 any  defaults from inherited declarations of the col-
	      umn. Otherwise, any parents that specify default values for  the
	      column  must  all	 specify the same default, or an error will be
	      reported.

       LIKE parent_table [ { INCLUDING | EXCLUDING } DEFAULTS ]
	      The LIKE clause specifies a table from which the new table auto-
	      matically	 copies	 all column names, their data types, and their
	      not-null constraints.

	      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 possi-
	      ble  to  include	data of the new table in scans of the original
	      table.

	      Default expressions for the copied column definitions will  only
	      be copied if INCLUDING DEFAULTS is specified. The default behav-
	      ior is to exclude default expressions, resulting in all  columns
	      of the new table having null defaults.

       WITH OIDS

       WITHOUT OIDS
	      This  optional  clause  specifies	 whether rows of the new table
	      should have OIDs (object identifiers) assigned to them. If  nei-
	      ther  WITH OIDS nor WITHOUT OIDS is specified, the default value
	      depends upon the default_with_oids configuration parameter.  (If
	      the new table inherits from any tables that have OIDs, then WITH
	      OIDS is forced even if the command says WITHOUT OIDS.)

	      If WITHOUT OIDS 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)].

       CONSTRAINT constraint_name
	      An optional name for a column or table constraint. If not speci-
	      fied, the system generates a name.

       NOT NULL
	      The column is not allowed to contain null values.

       NULL   The column is allowed  to	 contain  null	values.	 This  is  the
	      default.

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

       UNIQUE (column constraint)

       UNIQUE ( column_name [, ... ] ) (table constraint)
	      The UNIQUE constraint specifies that a  group  of	 one  or  more
	      columns  of a table may contain only unique values. The behavior
	      of the unique table constraint is the same as  that  for	column
	      constraints,  with  the  additional  capability to span multiple
	      columns.

	      For the purpose of a unique constraint, null values are not con-
	      sidered 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.)

       PRIMARY KEY (column constraint)

       PRIMARY KEY ( column_name [, ... ] ) (table constraint)
	      The primary key constraint specifies that a column or columns of
	      a table may contain only unique (non-duplicate), nonnull values.
	      Technically, PRIMARY KEY is merely a combination of  UNIQUE  and
	      NOT  NULL,  but identifying a set of columns as primary key also
	      provides metadata about the design of the schema, as  a  primary
	      key implies that other tables may rely on this set of columns as
	      a unique identifier for rows.

	      Only one primary key can be specified for a table, whether as  a
	      column constraint or a table constraint.

	      The  primary key constraint should name a set of columns that is
	      different from other sets of columns named by  any  unique  con-
	      straint defined for the same table.

       CHECK (expression)
	      The  CHECK  clause  specifies  an expression producing a Boolean
	      result which new or updated rows must satisfy for an  insert  or
	      update  operation	 to succeed. Expressions evaluating to TRUE or
	      UNKNOWN succeed. Should any row of an insert or update operation
	      produce  a  FALSE	 result	 an  error exception is raised and the
	      insert or update does not alter the database. A check constraint
	      specified	 as a column constraint should reference that column's
	      value only, while an expression appearing in a table  constraint
	      may reference multiple columns.

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

       REFERENCES reftable [ ( refcolumn ) ] [ MATCH matchtype ] [  ON	DELETE
       action ] [ ON UPDATE action ] (column constraint)

       FOREIGN KEY ( column [, ... ] )
	      These clauses specify a foreign key constraint,  which  requires
	      that  a  group of one or more columns of the new table must only
	      contain values that match values in the referenced column(s)  of
	      some  row	 of the referenced table. If refcolumn is omitted, the
	      primary key of the reftable is used. The referenced columns must
	      be the columns of a unique or primary key constraint in the ref-
	      erenced table. Note that foreign	key  constraints  may  not  be
	      defined between temporary tables and permanent tables.

	      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 refer-
	      enced column is not actually changed, no action is done.	Refer-
	      ential  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
		     Produce  an  error indicating that the deletion or update
		     would create a foreign key constraint violation.  If  the
		     constraint	 is  deferred,	this error will be produced at
		     constraint check time if there still exist any  referenc-
		     ing rows. This is the default action.

	      RESTRICT
		     Produce  an  error indicating that the deletion or update
		     would create a foreign key constraint violation.  This is
		     the  same	as  NO	ACTION	except	that  the check is not
		     deferrable.

	      CASCADE
		     Delete any rows referencing the deleted  row,  or	update
		     the  value	 of the referencing column to the new value of
		     the referenced column, respectively.

	      SET NULL
		     Set the referencing column(s) to null.

	      SET DEFAULT
		     Set the referencing column(s) to their default values.


       If the referenced column(s) are changed frequently, it may 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	 effi-
       ciently.

       DEFERRABLE

       NOT DEFERRABLE
	      This  controls  whether  the  constraint can be deferred. A con-
	      straint that is not deferrable will be checked immediately after
	      every  command.  Checking of constraints that are deferrable may
	      be postponed until the end of the	 transaction  (using  the  SET
	      CONSTRAINTS  [set_constraints(7)]	 command).   NOT DEFERRABLE is
	      the default. Only foreign key constraints currently accept  this
	      clause. All other constraint types are not deferrable.

       INITIALLY IMMEDIATE

       INITIALLY DEFERRED
	      If a constraint is deferrable, this clause specifies the default
	      time to check the constraint. If	the  constraint	 is  INITIALLY
	      IMMEDIATE,  it  is  checked  after  each	statement. This is the
	      default. If the constraint is INITIALLY DEFERRED, it is  checked
	      only  at	the  end of the transaction. The constraint check time
	      can be altered with  the	SET  CONSTRAINTS  [set_constraints(7)]
	      command.

       ON COMMIT
	      The  behavior  of	 temporary  tables at the end of a transaction
	      block can be controlled using ON COMMIT.	The three options are:

	      PRESERVE ROWS
		     No	 special  action is taken at the ends of transactions.
		     This is the default behavior.

	      DELETE ROWS
		     All rows in the temporary table will be  deleted  at  the
		     end  of each transaction block. Essentially, an automatic
		     truncate(7) is done at each commit.

	      DROP   The temporary table will be dropped at  the  end  of  the
		     current transaction block.


       TABLESPACE tablespace
	      The  tablespace  is  the name of the tablespace in which the new
	      table is to be created.  If not specified, default_tablespace is
	      used, or the database's default tablespace if default_tablespace
	      is an empty string.

       USING INDEX TABLESPACE tablespace
	      This clause allows selection of  the  tablespace	in  which  the
	      index associated with a UNIQUE or PRIMARY KEY constraint will be
	      created.	If not specified, default_tablespace is used,  or  the
	      database's  default tablespace if default_tablespace is an empty
	      string.

NOTES
       Using OIDs in new applications  is  not	recommended:  where  possible,
       using  a	 SERIAL or other sequence generator as the table's primary key
       is preferred. However, if your application does make  use  of  OIDs  to
       identify specific rows of a table, it is recommended to create a unique
       constraint on the oid column of that table, to ensure that OIDs in  the
       table will indeed uniquely identify rows even after counter wraparound.
       Avoid assuming that OIDs are  unique  across  tables;  if  you  need  a
       database-wide  unique  identifier,  use the combination of tableoid and
       row OID for the purpose.

	      Tip: The use of WITHOUT OIDS 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.


       PostgreSQL automatically creates an index for  each  unique  constraint
       and  primary key constraint to enforce uniqueness. Thus, it is not nec-
       essary to create an index explicitly for primary key columns. (See CRE-
       ATE INDEX [create_index(7)] for more information.)

       Unique  constraints  and	 primary keys are not inherited in the current
       implementation. This makes the combination of  inheritance  and	unique
       constraints rather dysfunctional.

       A table cannot have more than 1600 columns. (In practice, the effective
       limit is lower because of tuple-length constraints.)

EXAMPLES
       Create table films and table distributors:

       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 a table with a 2-dimensional array:

       CREATE TABLE array_int (
	   vector  int[][]
       );


       Define a unique table constraint for the table films. Unique table con-
       straints can be defined on one or more columns of the table.

       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)
       );


       Define a check column constraint:

       CREATE TABLE distributors (
	   did	   integer CHECK (did > 100),
	   name	   varchar(40)
       );


       Define a check table constraint:

       CREATE TABLE distributors (
	   did	   integer,
	   name	   varchar(40)
	   CONSTRAINT con1 CHECK (did > 100 AND name <> '')
       );


       Define  a primary key table constraint for the table films. Primary key
       table constraints can be defined on one or more columns of the table.

       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)
       );


       Define a primary key constraint for table distributors.	The  following
       two  examples are equivalent, the first using the table constraint syn-
       tax, the second the column constraint syntax.

       CREATE TABLE distributors (
	   did	   integer,
	   name	   varchar(40),
	   PRIMARY KEY(did)
       );


       CREATE TABLE distributors (
	   did	   integer PRIMARY KEY,
	   name	   varchar(40)
       );


       This assigns a literal constant default	value  for  the	 column	 name,
       arranges for the default value of column did to be generated by select-
       ing the next value of a sequence object, and makes the default value of
       modtime be the time at which the row is inserted.

       CREATE TABLE distributors (
	   name	     varchar(40) DEFAULT 'Luso Films',
	   did	     integer DEFAULT nextval('distributors_serial'),
	   modtime   timestamp DEFAULT current_timestamp
       );


       Define  two  NOT NULL column constraints on the table distributors, one
       of which is explicitly given a name:

       CREATE TABLE distributors (
	   did	   integer CONSTRAINT no_null NOT NULL,
	   name	   varchar(40) NOT NULL
       );


       Define a unique constraint for the name column:

       CREATE TABLE distributors (
	   did	   integer,
	   name	   varchar(40) UNIQUE
       );

       The above is equivalent to the following	 specified  as	a  table  con-
       straint:

       CREATE TABLE distributors (
	   did	   integer,
	   name	   varchar(40),
	   UNIQUE(name)
       );


       Create table cinemas in tablespace diskvol1:

       CREATE TABLE cinemas (
	       id serial,
	       name text,
	       location text
       ) TABLESPACE diskvol1;


COMPATIBILITY
       The  CREATE TABLE command conforms to the SQL standard, with exceptions
       listed below.

   TEMPORARY TABLES
       Although the syntax of CREATE TEMPORARY TABLE resembles that of the SQL
       standard, the effect is not the same. In the standard, temporary tables
       are defined just once and automatically exist (starting with empty con-
       tents)  in  every session that needs them.  PostgreSQL instead requires
       each session to issue its own CREATE TEMPORARY TABLE command  for  each
       temporary  table	 to be used. This allows different sessions to use the
       same temporary table name for different	purposes,  whereas  the	 stan-
       dard's  approach	 constrains  all  instances of a given temporary table
       name to have the same table structure.

       The standard's definition of the behavior of temporary tables is widely
       ignored. PostgreSQL's behavior on this point is similar to that of sev-
       eral other SQL databases.

       The standard's distinction between global and local temporary tables is
       not  in	PostgreSQL,  since  that distinction depends on the concept of
       modules, which PostgreSQL does not  have.   For	compatibility's	 sake,
       PostgreSQL will accept the GLOBAL and LOCAL keywords in a temporary ta-
       ble declaration, but they have no effect.

       The ON COMMIT clause for temporary tables also resembles the SQL	 stan-
       dard,  but  has	some differences.  If the ON COMMIT clause is omitted,
       SQL specifies that the default behavior is ON COMMIT DELETE ROWS.  How-
       ever,  the  default  behavior in PostgreSQL is ON COMMIT PRESERVE ROWS.
       The ON COMMIT DROP option does not exist in SQL.

   COLUMN CHECK CONSTRAINTS
       The SQL standard says that CHECK column constraints may only  refer  to
       the  column  they  apply	 to; only CHECK table constraints may refer to
       multiple columns.  PostgreSQL does not  enforce	this  restriction;  it
       treats column and table check constraints alike.

   NULL ''CONSTRAINT''
       The  NULL  ''constraint''  (actually  a non-constraint) is a PostgreSQL
       extension to the SQL standard that is included for  compatibility  with
       some  other  database  systems (and for symmetry with the NOT NULL con-
       straint). Since it is the default for any column, its presence is  sim-
       ply noise.

   INHERITANCE
       Multiple	 inheritance  via the INHERITS clause is a PostgreSQL language
       extension.  SQL:1999 and later define single inheritance using  a  dif-
       ferent  syntax  and  different semantics. SQL:1999-style inheritance is
       not yet supported by PostgreSQL.

   OBJECT IDS
       The PostgreSQL concept of OIDs is not standard.

   ZERO-COLUMN TABLES
       PostgreSQL allows a table of no columns to  be  created	(for  example,
       CREATE TABLE foo();). This is an extension from the SQL standard, which
       does not allow zero-column tables. Zero-column tables are not in	 them-
       selves  very useful, but disallowing them creates odd special cases for
       ALTER TABLE DROP COLUMN, so  it	seems  cleaner	to  ignore  this  spec
       restriction.

   TABLESPACES
       The  PostgreSQL	concept	 of  tablespaces  is not part of the standard.
       Hence, the clauses TABLESPACE and USING	INDEX  TABLESPACE  are	exten-
       sions.

SEE ALSO
       ALTER   TABLE  [alter_table(7)],	 DROP  TABLE  [drop_table(l)],	CREATE
       TABLESPACE [create_tablespace(l)]



SQL - Language Statements	  2010-12-14			CREATE TABLE()
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