CREATE SEQUENCE

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CREATE SEQUENCE�ϡ��ֹ��ޤ�� ϡ�name�Ȥ��̾��ä��Ԥ��ο��ü�ʥơ��֥�κ��Ƚ��Ԥ��ޤ�� ֹ��ϡ��Υ��ޥ�ɤ�¹Ԥ��桼��ˤ�äƽ�ͭ��ޤ��

��̾��Ϳ��Ƥ��硢��Υ��󥹤ϻ��ꤵ�줿��ޤǺ��ޤ�� ̾��ʤ��С��󥹤ϸ��ߤΥ��ޤǺ��ޤ�� ޤ��󥹤��̤ʥ��ޤ�¸�ߤ��뤿�ᡢ��󥹤κ��˥��̾��Ϳ��뤳�ȤϤǤ��ޤ�� ̾�ϡ�Ʊ��¾�Υ��󥹡��ơ��֥롢��ǥå��⤷��ϥӥ塼�Ȥϰۤʤ�̾��ˤ��ɬ�פ��ޤ��

��󥹤��塢nextval��currval��setval�ؿ��Ѥ��ƥ��󥹤���ޤ�� δؿ��9.12��Ƥ��ޤ��

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SELECT * FROM name;

��Ѥ��ȡ��󥹤Υѥ�᡼��ȸ��ߤξ��֤��ǧ��뤳�Ȥ��Ǥ��ޤ�� äˡ��󥹤�last_value�ե��ɤ��ƤΥ��å��ǳ��Ƥ�줿�Ǹ��ͤ򼨤��ޤ�� (��󡢤��ͤ�ɽ��줿��ǡ�¾�Υ��å��nextval�μ¹Ԥˤ��Ť��ʤäƤ��⤢��ޤ��)

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TEMPORARY�⤷��TEMP

��ꤵ�줿��硢��Υ��󥹥��֥��ȤϤ��Υ��å��Ѥ��Ȥ��ƺ��졢��å��λ��˼�ưŪ�˺��ޤ�� 󥹤�¸�ߤ��硢Ʊ��̾��Ĵ�¸�α�³��󥹤ϥ��޽��줿̾��ǻ��Ȥ��Ƥ��ʤ��С�(��Υ��å��Ǥ�)��Ļ�Ǥ��

name

��륷��󥹤�̾��Ǥ� (��޽��̾�Ǥ��)��

increment

��ά��ǽ��INCREMENT BY increment��ϡ��ߤΥ��󥹤��ͤ��鿷��ͤ��ޤ��̤��ꤷ�ޤ�� ͤϾ��Υ��󥹡��ͤϹ߽�Υ��󥹤��ޤ�� ꤷ�ʤ��Υǥե��ͤ�1�Ǥ��

minvalue NO MINVALUE

��ά��ǽ��MINVALUE minvalue��ϡ��󥹤Ȥ��ƺ��Ǥ��Ǿ��ͤ��ꤷ�ޤ�� ζ�λ��꤬�ʤ��⤷��ϡ�NO MINVALUE��ꤵ�줿��硢�ǥե��Ȥ��Ѥ��ޤ�� ȹ߽�Υ��󥹤Υǥե��ͤϡ��줾��1��-(2⁶³-1)�Ǥ��

maxvalue NO MAXVALUE

��ά��ǽ��MAXVALUE maxvalue��ϡ��󥹤κ��ͤ��ꤷ�ޤ�� ζ�λ��꤬�ʤ��⤷��ϡ�NO MAXVALUE��ꤵ�줿��硢�ǥե��Ȥ��Ѥ��ޤ�� ȹ߽�Τ��줾��Υ��ֹ�κ��ͤΥǥե��Ȥϡ�2⁶³-1��-1�Ǥ��

start

��ά��ǽ��START WITH start��ˤ�äơ��󥹤�ɤ��Ǥ�Ϥ�뤳�Ȥ��Ǥ��ޤ�� ǥե��ȤǤϡ��ֹ椬�Ϥޤ��ͤϡ��ξ��minvalue�ˡ��߽�ξ��maxvalue�ˤʤ�ޤ��

cache

CACHE cache��ץ��ϡ��ɤΤ��餤�ο��Υ��ֹ�򤢤餫��ֹ��ơ��˳�Ǽ��뤫��ꤷ�ޤ��ˤ�ꥢ��®�ˤ��뤳�Ȥ��Ǥ��ޤ�� Ǿ��ͤ�1�ʤ��1��ˤĤ�1�Ĥ��ͤ��ޤ��Ĥޤꥭ��å��Ϥ��ޤ��ˤǡ��줬�ǥե��Ȥˤ�ʤäƤ��ޤ��

CYCLE NO CYCLE

CYCLE��ץ��ˤ�äơ��硢��뤤�Ϲ߽�Υ��ֹ椬��줾��maxvalue�ޤ��minvalue��ͤ�ã��ˡ��󥹤򸵤��᤹��Ȥ��Ǥ��ޤ�� ⤷��ֹ�θ³��ͤޤ�ã��硢��ֹ��minvalue�ޤ��maxvalue�Τɤ��餫�ˤʤ�ޤ��

NO CYCLE��ꤵ�줿��硢��¤�ã��nextval�ƤӽФ��ϥ��顼�ˤʤ�ޤ�� CYCLE��NO CYCLE��ꤵ��ʤ��ϡ�NO CYCLE��ǥե��ȤǤ��

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��󥹤��ˤ�DROP SEQUENCE��Ѥ��Ƥ��

��󥹤�bigint��Ѥ˴�Ť��Ƥ��ޤ�� Τ��ᡢ8�Х��ϰ�(-9223372036854775808��9223372036854775807�ޤ�)��ۤ��뤳�ȤϤǤ��ޤ�� Ť�Υץ�åȥե��Ǥϡ�8�Х��򥵥ݡ��Ȥ��륳��ѥ��餬�ʤ��Ȥ��ޤ�� ξ�硢��󥹤��̾��integer��Ѥ��Ѥ��ޤ��(��ϰϤ�-2147483648��+2147483647�ޤǤǤ��)

1��礭��ͤ��ꤵ�줿cache��󥹥��֥��Ȥǻ��Ѥ��줿��硢��Υ��󥹤�ʣ��Υ��å��Ʊ��˻��Ѥ��ͽ�۳��η�̤ˤʤ��礬��ޤ�� ƥ��å��ϡ��å��󤬥��󥹥��֥��Ȥ˥��ȡ�Ϣ³��륷��ͤ��ƥ��å��夷�ޤ�� ơ��ȼ��󥹥��֥��Ȥ�last_value��ä��ޤ�� ˤ�ꡢ��Υ��å��ˤ��뤽�θ��cache-1��λ��ѤǤϡ��ƺѤߤ��ͤ�ñ��֤��󥹥��֥��Ȥ��ѹ��ޤ�� å��ˤ��Ƴ��Ƥ�줿��Ѥ��ʤ��ä��ֹ�ϡ��å��ν�λ��Ƽ��ޤ��Τǡ��̤Ȥ��ƥ��󥹤�"��"��Ǥ��ޤ��

��ˡ�ʣ��Υ��å��ˤϸ��̤Υ��ͤ��Ƥ��뤳�Ȥ��ݾڤ��Ƥ��ޤ��ƤΥ��å��º�Ť��ȡ��󥹤��ͤϽ��̤�ˤʤ�ʤ��Ȥ��ޤ�� 㤨�С�cache��10�ξ��ͤ��ޤ�� å��A�Ǥ�1��10�ޤǤ��ݤ��nextval=1��֤��ޤ�� å��B�Ǥϡ��å��A��nextval=2��֤��ˡ�11��20��ݤ��nextval=11��֤��ޤ�� äơ�cache��1��ꤷ��nextval��Ϣ³��ͤ��뤳�Ȥ��Ȥ��Ƥ��ꤢ��ޤ��󤬡�1��礭��ͤ�cache��ꤵ��ȡ�nextval��ͤ��Ϣ³��Ƥ��ΤǤϤʤ��ۤʤ��ͤȤʤ�Ȥ��Ȥ��Ȥ��뤳�Ȥ��Ǥ��ޤ�� ޤ��last_value�ϡ��ͤ�nextval��֤��줿��ɤ��˴ط��ʤ��ƤΥ��å��ǳ��ݤ��줿�Ǹ��ͤ�ȿ�Ǥ��ޤ��

��¾��ä��󥹤��Ф��Ƽ¹Ԥ��setval��¾�Υ��å��Ǥϡ��å��夷��ƺѤ��ͤ��ƻȤ��̤��ޤǡ�ʬ��ʤ��Ȥ��Ȥ��θ��٤��Ǥ��

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101��Ϥޤ�serial�Ȥ��̾��ξ��祷��󥹤��ޤ��

CREATE SEQUENCE serial START 101;

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SELECT nextval('serial');
    
 nextval
---------
     114

��Υ��󥹤�INSERT��ޥ�ɤǻ��Ѥ��ޤ��

INSERT INTO distributors VALUES (nextval('serial'), 'nothing');

COPY FROM�θ�ǥ��ͤ򹹿��ޤ��

BEGIN;
COPY distributors FROM 'input_file';
SELECT setval('serial', max(id)) FROM distributors;
END;

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CREATE SEQUENCE��SQL:2003�ǵ��ꤵ��Ƥ��ޤ�� PostgreSQL�ϡ��ʲ��㳰��ɸ��˽��ޤ��

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��ͤ��Ф��ˤϡ�ɸ��NEXT VALUE FOR��ǤϤʤ�nextval()�ؿ��Ѥ��ޤ��

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