Man Pages

alter_sequence(7) - phpMan alter_sequence(7) - phpMan

Command: man perldoc info search(apropos)  


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 own-
       ing 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 nega-
              tive 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 MIN-
              VALUE 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  com-
              mands will use.

       restart
              The  optional clause RESTART [ WITH restart ] changes the current value of the sequence. This is equiva-
              lent 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 unspeci-
              fied, 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  min-
              value 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 speci-
              fied, this association replaces any previously specified association for the sequence. The specified ta-
              ble  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 generation 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         2014-02-17                 ALTER SEQUENCE(7)