ALTER 
SEQUENCE(7)						   SQL Commands 						 ALTER SEQUENCE(7)

NAME

       ALTER SEQUENCE - change the definition of a sequence generator

SYNOPSIS

       ALTER SEQUENCE name [ INCREMENT [ BY ] increment ]
	   [ MINVALUE minvalue | NO MINVALUE ] [ MAXVALUE maxvalue | NO MAXVALUE ]
	   [ START [ WITH ] start ]
	   [ RESTART [ [ WITH ] restart ] ]
	   [ CACHE cache ] [ [ NO ] CYCLE ]
	   [ OWNED BY { table.column | NONE } ]
       ALTER SEQUENCE name OWNER TO new_owner
       ALTER SEQUENCE name RENAME TO new_name
       ALTER SEQUENCE name SET SCHEMA new_schema

DESCRIPTION

       ALTER  SEQUENCE changes the parameters of an existing sequence generator. Any parameters not specifically set in the ALTER SEQUENCE command
       retain their prior settings.

       You must own the sequence to use ALTER SEQUENCE.  To change a sequence's schema, you must also have CREATE privilege on the new schema.	To
       alter  the  owner,  you	must  also  be a direct or indirect member of the new owning role, and that role must have CREATE privilege on the
       sequence's schema. (These restrictions enforce that altering the owner doesn't do anything you couldn't do by dropping and  recreating  the
       sequence.  However, a superuser can alter ownership of any sequence anyway.)

PARAMETERS

       name   The name (optionally schema-qualified) of a sequence to be altered.

       increment
	      The  clause  INCREMENT  BY  increment  is  optional.  A  positive value will make an ascending sequence, a negative one a descending
	      sequence. If unspecified, the old increment value will be maintained.

       minvalue

       NO MINVALUE
	      The optional clause MINVALUE minvalue determines the minimum value a sequence  can  generate.  If  NO  MINVALUE  is  specified,  the
	      defaults	of  1  and  -263-1 for ascending and descending sequences, respectively, will be used. If neither option is specified, the
	      current minimum value will be maintained.

       maxvalue

       NO MAXVALUE
	      The optional clause MAXVALUE maxvalue determines the maximum value for the sequence. If NO MAXVALUE is specified, the  defaults  are
	      263-1 and -1 for ascending and descending sequences, respectively, will be used. If neither option is specified, the current maximum
	      value will be maintained.

       start  The optional clause START WITH start changes the recorded start value of the sequence. This has no effect on  the  current  sequence
	      value; it simply sets the value that future ALTER SEQUENCE RESTART commands will use.

       restart
	      The  optional  clause  RESTART  [ WITH restart ] changes the current value of the sequence. This is equivalent to calling the setval
	      function with is_called = false: the specified value will be returned by the next call of nextval.  Writing RESTART with no  restart
	      value is equivalent to supplying the start value that was recorded by CREATE SEQUENCE or last set by ALTER SEQUENCE START WITH.

       cache  The  clause  CACHE  cache enables sequence numbers to be preallocated and stored in memory for faster access. The minimum value is 1
	      (only one value can be generated at a time, i.e., no cache). If unspecified, the old cache value will be maintained.

       CYCLE  The optional CYCLE key word can be used to enable the sequence to wrap around when the maxvalue or minvalue has been reached  by	an
	      ascending  or descending sequence respectively. If the limit is reached, the next number generated will be the minvalue or maxvalue,
	      respectively.

       NO CYCLE
	      If the optional NO CYCLE key word is specified, any calls to nextval after the sequence has reached its maximum value will return an
	      error.  If neither CYCLE or NO CYCLE are specified, the old cycle behavior will be maintained.

       OWNED BY table.column

       OWNED BY NONE
	      The OWNED BY option causes the sequence to be associated with a specific table column, such that if that column (or its whole table)
	      is dropped, the sequence will be automatically dropped as well. If specified, this association  replaces	any  previously  specified
	      association  for	the  sequence. The specified table must have the same owner and be in the same schema as the sequence.	Specifying
	      OWNED BY NONE removes any existing association, making the sequence ``free-standing''.

       new_owner
	      The user name of the new owner of the sequence.

       new_name
	      The new name for the sequence.

       new_schema
	      The new schema for the sequence.

NOTES

       To avoid blocking of concurrent transactions that obtain numbers from the same sequence, ALTER SEQUENCE's effects on the  sequence  genera-
       tion  parameters  are  never  rolled  back;  those changes take effect immediately and are not reversible. However, the OWNED BY, OWNER TO,
       RENAME TO, and SET SCHEMA clauses cause ordinary catalog updates that can be rolled back.

       ALTER SEQUENCE will not immediately affect nextval results in backends, other  than  the  current  one,	that  have  preallocated  (cached)
       sequence  values. They will use up all cached values prior to noticing the changed sequence generation parameters. The current backend will
       be affected immediately.

       ALTER SEQUENCE does not affect the currval status for the sequence. (Before PostgreSQL 8.3, it sometimes did.)

       For historical reasons, ALTER TABLE can be used with sequences too; but the only variants of ALTER TABLE that are  allowed  with  sequences
       are equivalent to the forms shown above.

EXAMPLES

       Restart a sequence called serial, at 105:

       ALTER SEQUENCE serial RESTART WITH 105;

COMPATIBILITY

       ALTER  SEQUENCE	conforms  to the SQL standard, except for the START WITH, OWNED BY, OWNER TO, RENAME TO, and SET SCHEMA clauses, which are
       PostgreSQL extensions.

SEE ALSO

       CREATE SEQUENCE [create_sequence(7)], DROP SEQUENCE [drop_sequence(7)]

SQL - Language Statements					    2010-05-14							 ALTER SEQUENCE(7)