{"id":345,"date":"2011-11-23T21:50:09","date_gmt":"2011-11-23T13:50:09","guid":{"rendered":"https:\/\/blog.rexdf.org\/?p=345"},"modified":"2011-11-23T21:50:09","modified_gmt":"2011-11-23T13:50:09","slug":"create-sequence","status":"publish","type":"post","link":"https:\/\/blog.rexdf.org\/ja\/2011\/11\/create-sequence\/","title":{"rendered":"create sequence"},"content":{"rendered":"

\u5728oracle\u4e2dsequence\u5c31\u662f\u6240\u8c13\u7684\u5e8f\u5217\u53f7\uff0c\u6bcf\u6b21\u53d6\u7684\u65f6\u5019\u5b83\u4f1a\u81ea\u52a8\u589e\u52a0\uff0c\u4e00\u822c\u7528\u5728\u9700\u8981\u6309
\n\u5e8f\u5217\u53f7\u6392\u5e8f\u7684\u5730\u65b9\u3002
\n1\u3001 create sequence
\n\u4f60\u9996\u5148\u8981\u6709create sequence\u6216\u8005create any sequence\u6743\u9650\uff0c
\ncreate sequence emp_sequence
\nINCREMENT BY 1 — \u6bcf\u6b21\u52a0\u51e0\u4e2a
\nSTART WITH 1 — \u4ece1\u5f00\u59cb\u8ba1\u6570
\nNOMAXVALUE — \u4e0d\u8bbe\u7f6e\u6700\u5927\u503c
\nNOCYCLE — \u4e00\u76f4\u7d2f\u52a0\uff0c\u4e0d\u5faa\u73af
\nCACHE 10;<\/p>\n

\u4e00\u65e6\u5b9a\u4e49\u4e86emp_sequence\uff0c\u4f60\u5c31\u53ef\u4ee5\u7528CURRVAL\uff0cNEXTVAL
\nCURRVAL=\u8fd4\u56desequence\u7684\u5f53\u524d\u503c
\nNEXTVAL=\u589e\u52a0sequence\u7684\u503c\uff0c\u7136\u540e\u8fd4\u56desequence\u503c
\n\u6bd4\u5982\uff1a
\nemp_sequence.CURRVAL
\nemp_sequence.NEXTVAL<\/p>\n

\u53ef\u4ee5\u4f7f\u7528sequence\u7684\u5730\u65b9\uff1a
\n– \u4e0d\u5305\u542b\u5b50\u67e5\u8be2\u3001snapshot\u3001VIEW\u7684 SELECT \u8bed\u53e5
\n– INSERT\u8bed\u53e5\u7684\u5b50\u67e5\u8be2\u4e2d
\n– NSERT\u8bed\u53e5\u7684VALUES\u4e2d
\n– UPDATE \u7684 SET\u4e2d<\/p>\n

\u53ef\u4ee5\u770b\u5982\u4e0b\u4f8b\u5b50\uff1a
\nINSERT INTO emp VALUES
\n(empseq.nextval, ‘LEWIS’, ‘CLERK’,7902, SYSDATE, 1200, NULL, 20);<\/p>\n

SELECT empseq.currval FROM DUAL;<\/p>\n

\u4f46\u662f\u8981\u6ce8\u610f\u7684\u662f\uff1a
\n– \u7b2c\u4e00\u6b21NEXTVAL\u8fd4\u56de\u7684\u662f\u521d\u59cb\u503c\uff1b\u968f\u540e\u7684NEXTVAL\u4f1a\u81ea\u52a8\u589e\u52a0\u4f60\u5b9a\u4e49\u7684INCREMENT BY\u503c\uff0c
\n\u7136\u540e\u8fd4\u56de\u589e\u52a0\u540e\u7684\u503c\u3002CURRVAL \u603b\u662f\u8fd4\u56de\u5f53\u524dsequence\u7684\u503c\uff0c\u4f46\u662f\u5728\u7b2c\u4e00\u6b21NEXTVAL
\n\u521d\u59cb\u5316\u4e4b\u540e\u624d\u80fd\u4f7f\u7528CURRVAL\uff0c\u5426\u5219\u4f1a\u51fa\u9519\u3002\u4e00\u6b21NEXTVAL\u4f1a\u589e\u52a0\u4e00\u6b21sequence\u7684\u503c\uff0c
\n\u6240\u4ee5\u5982\u679c\u4f60\u5728\u540c\u4e00\u4e2a\u8bed\u53e5\u91cc\u9762\u4f7f\u7528\u591a\u4e2aNEXTVAL\uff0c\u5176\u503c\u5c31\u662f\u4e0d\u4e00\u6837\u7684\u3002\u660e\u767d\uff1f
\n– \u5982\u679c\u6307\u5b9aCACHE\u503c\uff0coracle\u5c31\u53ef\u4ee5\u9884\u5148\u5728\u5185\u5b58\u91cc\u9762\u653e\u7f6e\u4e00\u4e9bsequence\uff0c\u8fd9\u6837\u5b58\u53d6\u7684\u5feb
\n\u4e9b\u3002
\ncache\u91cc\u9762\u7684\u53d6\u5b8c\u540e\uff0coracle\u81ea\u52a8\u518d\u53d6\u4e00\u7ec4\u5230cache\u3002 \u4f7f\u7528cache\u6216\u8bb8\u4f1a\u8df3\u53f7\uff0c \u6bd4\u5982
\n\u6570\u636e\u5e93\u7a81\u7136\u4e0d\u6b63\u5e38down\u6389\uff08shutdown abort),cache\u4e2d\u7684sequence\u5c31\u4f1a\u4e22\u5931. \u6240\u4ee5\u53ef
\n\u4ee5\u5728create sequence\u7684\u65f6\u5019\u7528nocache\u9632\u6b62\u8fd9\u79cd\u60c5\u51b5\u3002<\/p>\n

2\u3001 Alter sequence
\n\u4f60\u6216\u8005\u662f\u8be5sequence\u7684owner\uff0c\u6216\u8005\u6709ALTER ANY sequence\u6743\u9650\u624d\u80fd\u6539\u52a8sequence\u3002 \u53ef
\n\u4ee5alter\u9664start\u503c\u4e4b\u5916\u7684\u6240\u6709sequence\u53c2\u6570\u3002\u5982\u679c\u60f3\u8981\u6539\u53d8start\u503c\uff0c\u5fc5\u987bdrop sequence
\n\u518dre-create\u3002\u4f8b\u5b50\uff1a
\nALTER sequence emp_sequence
\nINCREMENT BY 10
\nMAXVALUE 10000
\nCYCLE — \u523010000\u540e\u4ece\u5934\u5f00\u59cb
\nNOCACHE;<\/p>\n

\u5f71\u54cdsequence\u7684\u521d\u59cb\u5316\u53c2\u6570\uff1a
\nsequence_CACHE_ENTRIES =
\n\u8bbe\u7f6e\u80fd\u540c\u65f6\u88abcache\u7684sequence\u6570\u76ee\u3002<\/p>\n

\u53ef\u4ee5\u5f88\u7b80\u5355\u7684Drop sequence
\nDROP sequence order_seq;<\/p>\n

\u7ed3\u675f<\/p>\n","protected":false},"excerpt":{"rendered":"

\u5728oracle\u4e2dsequence\u5c31\u662f\u6240\u8c13\u7684\u5e8f\u5217\u53f7\uff0c\u6bcf\u6b21\u53d6\u7684\u65f6\u5019\u5b83\u4f1a\u81ea\u52a8\u589e\u52a0\uff0c\u4e00\u822c … \u7d9a\u304d\u3092\u8aad\u3080 →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[6],"tags":[50],"class_list":["post-345","post","type-post","status-publish","format-standard","hentry","category-oracle","tag-oracle-2"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/blog.rexdf.org\/ja\/wp-json\/wp\/v2\/posts\/345","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.rexdf.org\/ja\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.rexdf.org\/ja\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.rexdf.org\/ja\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.rexdf.org\/ja\/wp-json\/wp\/v2\/comments?post=345"}],"version-history":[{"count":0,"href":"https:\/\/blog.rexdf.org\/ja\/wp-json\/wp\/v2\/posts\/345\/revisions"}],"wp:attachment":[{"href":"https:\/\/blog.rexdf.org\/ja\/wp-json\/wp\/v2\/media?parent=345"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.rexdf.org\/ja\/wp-json\/wp\/v2\/categories?post=345"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.rexdf.org\/ja\/wp-json\/wp\/v2\/tags?post=345"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}