{"id":8489,"date":"2021-09-26T09:08:21","date_gmt":"2021-09-26T01:08:21","guid":{"rendered":"http:\/\/www.hefeiyu.com\/?p=8489"},"modified":"2021-09-30T09:38:37","modified_gmt":"2021-09-30T01:38:37","slug":"day21-fgl-%e7%a8%8b%e5%ba%8f%e5%bc%80%e5%8f%914-%e6%9f%a5%e8%af%a2%e6%9d%a1%e4%bb%b6%e8%be%93%e5%85%a5qbe-query-by-example","status":"publish","type":"post","link":"https:\/\/www.hefeiyu.com\/?p=8489","title":{"rendered":"[day21] FGL \u7a0b\u5e8f\u5f00\u53d1(4) – \u67e5\u8be2\u6761\u4ef6\u8f93\u5165(QBE: Query By Example)"},"content":{"rendered":"

\u6587\u7ae0\u6765\u81ea\uff1aiT \u90a6\u5e6b\u5fd9::\u4e00\u8d77\u5e6b\u5fd9\u89e3\u6c7a\u96e3\u984c\uff0c\u62ef\u6551 IT \u4eba\u7684\u4e00\u5929 (ithome.com.tw)<\/a><\/h2>\n

[day21] FGL \u7a0b\u5e8f\u5f00\u53d1(4) – \u67e5\u8be2\u6761\u4ef6\u8f93\u5165(QBE: Query By Example)<\/h2>\n

\u8fd9\u4e2a\u7ae0\u8282\u4e2d\uff0c\u6211\u4eec\u63a2\u8ba8\u56db\u7c7b\u67e5\u8be2\u6307\u4ee4\u4e2d\u5269\u4e0b\u7684 QBE \u6761\u4ef6\u8f93\u5165\u6307\u4ee4 CONSTRUCT\u3002\u505a\u5b8c\u6761\u4ef6\u7684\u8f93\u5165\u540e\u81ea\u7136\u5c31\u662f\u5c06\u67e5\u8be2\u8bed\u53e5\u7ec4\u88c5\u597d\uff0c\u4f20\u5230\u6570\u636e\u5e93\u5185\u5f00\u59cb\u641c\u5bfb\uff0c\u8fd9\u4e2a\u52a8\u4f5c\u4e0a\u4e5f\u6709\u4e00\u4e9b\u9700\u8981\u6ce8\u610f\u7684\uff0c\u5c06\u4f1a\u5728\u6b64\u6bb5\u540c\u65f6\u8fdb\u884c\u63d0\u9192\u3002<\/p>\n

CONSTRUCT \u67e5\u8be2\u6761\u4ef6\u8f93\u5165<\/h3>\n

\u56e0\u4e3a INPUT \u533a\u5206\u4e24\u79cd\u6307\u4ee4\u65b9\u5f0f\uff1a\u8f93\u5165\u7528\u7684\u753b\u9762\u5b57\u6bb5\u4e0e\u53d8\u91cf\u5143\u7d20\u53ef\u4ee5\u5bf9\u5e94\u7684(INPUT BY NAME) \u4e0e\u4e0d\u53ef\u5bf9\u5e94\u7684 (INPUT…FROM…)\uff0c\u56e0\u6b64 CONSTRUCT \u4e00\u6837\u53ef\u4ee5\u533a\u5206\u6210\u4e24\u79cd\uff1a<\/p>\n

    \n
  1. \u53ef\u4ee5\u5bf9\u5e94\u5143\u7d20\u7684 CONSTRUCT BY NAME str_where ON column1, column2, column3…<\/li>\n
  2. \u4e0d\u53ef\u4ee5\u5bf9\u5e94\u5143\u7d20\u7684 CONSTRUCT str_where ON column1, column2, column3… WHERE scr1, scr2, scr3…<\/li>\n<\/ol>\n

    \u8fd9\u4e24\u79cd\u6307\u4ee4\uff0c\u6700\u540e\u5f97\u5230\u7684\u90fd\u4f1a\u662f\u7ecf\u8fc7 FGL \u534f\u52a9\u7ec4\u88c5\u540e\u7684 WHERE \u5b57\u7b26\u4e32\u3002<\/p>\n

    \u4e3a\u4ec0\u4e48\u4e0d\u7528 INPUT \u6765\u505a\u4e00\u6837\u7684\u4e8b\u60c5\uff1f\u5982\u679c\u80fd\u63a7\u5236\u5230\u7279\u6b8a\u7b26\u53f7\u7684\u4f7f\u7528 (\u4f8b\u5982 :\u8f6c\u6362\u4e3a BETWEEN \u7b49)\uff0c\u6216\u662f\u5168\u90e8\u6ca1\u8f93\u5165\u65f6\u81ea\u52a8\u6539\u4e3a 1=1 \u8f93\u51fa\uff1b\u82e5\u505a\u5f97\u6765\u8fd9\u4ef6\u4e8b\uff0c\u53ef\u4ee5\u81ea\u884c\u6539\u7528 INPUT\u3002<\/p>\n

    \u63a7\u5236\u533a\u5757(Conteol Block)<\/h4>\n

    CONSTRUCT\u6307\u4ee4\u5e76\u4e0d\u7406\u4f1a\u662f\u5426\u4e3a ARRAY \u7684\u6570\u636e\uff0c\u56e0\u4e3a\u4ed6\u7684\u76ee\u7684\u53ea\u662f\u5728\u8be2\u95ee\u7528\u6237\u300e\u8981\u67e5\u8be2\u54ea\u4e9b\u5b57\u6bb5\u7684\u54ea\u4e9b\u6570\u636e\u300f\uff0c\u56e0\u6b64\u78b0\u5230 TABLE \u7684\u65f6\u5019\uff0c\u53ea\u9700\u8981\u6307\u5b9a\u4e00\u6392 (\u901a\u5e38\u662f\u7b2c\u4e00\u6392\uff0c\u5e94\u8be5\u4e0d\u4f1a\u6307\u5b9a\u7b2c 4518\u6392\u5427\uff1f) \u8ba9\u7528\u6237\u8fdb\u884c\u67e5\u8be2\u6570\u636e\u7684\u6307\u5b9a\u5c31\u53ef\u4ee5\u3002
    \n\u6240\u4ee5\u6574\u4f53\u7684\u63a7\u5236\u533a\u5757\uff0c\u4e0e INPUT \u6307\u4ee4\u76f8\u540c<\/strong>\uff0c\u57fa\u672c\u7684\u63a7\u5236 ON ACTION\/ ON IDLE\/ ON TIMER \u4e0e\u5b57\u6bb5\u63a7\u5236 BEFORE FIELD a \/ AFTER FIELD a \/ ON CHANGE a \u4e4b\u7c7b\u7684\u533a\u5757\u3002<\/p>\n

    \u53d6\u5f97 WHERE\u6761\u4ef6\u5230\u53d6\u51fa\u8d44\u6599<\/h3>\n

    \"\u5361\u901a\u4eba\u7269<\/p>\n

    \u6211\u4eec\u8bbe\u8ba1\u5b8c\u4e00\u5f20\u8868\u683c\u753b\u9762\u540e\uff0c\u81ea\u7136\u662f\u5e0c\u671b\u7528\u6237\u80fd\u591f\u5728\u91cc\u9762\u770b\u5230\u60f3\u67e5\u8be2\u7684\u6570\u636e\u3002\u900f\u8fc7\u8ba9\u7528\u6237\u6311\u9009\u5b57\u6bb5\u8fdb\u884c\u6570\u636e\u6307\u5b9a (\u5982\u679c\u4e0d\u8f93\u5165\u7684\u8bdd\u5c31\u662f\u6570\u636e\u5168\u9009\uff0cWHERE\u6761\u4ef6\u5219\u662f 1=1)\uff0c\u63a5\u4e0b\u6765\u8981\u505a\u7684\u5c31\u662f\u7ec4\u5408\u6761\u4ef6\u3001\u6267\u884cSQL\u3001\u6293\u53d6\u6570\u636e\u4e09\u6b65\u9aa4\u3002<\/p>\n

    PREPARE<\/h4>\n

    \u4f9d\u7167\u9700\u6c42\u8fdb\u884c SQL\u6307\u4ee4\u7684\u64b0\u5199\uff0c\u8fd9\u9053\u57fa\u672c\u9898\u5c31\u8ba9\u5404\u4f4d\u81ea\u884c\u7814\u7a76\u3002\u6211\u4eec\u900f\u8fc7<\/p>\n

    LET ls_sql=”SELECT ….WHERE “,where_condiction<\/p>\n

    \u7684\u65b9\u5f0f\u53ef\u4ee5\u5c06\u5b57\u7b26\u4e32\u7ec4\u88c5\u8d77\u6765\u3002\u5f53\u7136\uff0c\u5e76\u4e0d\u9650\u5b9a\u8bf4\u53ea\u80fd\u5c06 CONSTRUCT \u7684\u7ed3\u679c\u653e\u5728\u6b64\u5904\uff0c\u800c\u662f\u6709\u9700\u8981\u7684\u90fd\u53ef\u4ee5\u62ff\u6765\u8fd9\u91cc\u8fdb\u884c\u7ec4\u88c5\u3002\u7ec4\u88c5\u540e\uff0c\u8bf7\u8bb0\u5f97\u62ff\u5230\u7684\u662f\u300e** SQL\u5b57\u7b26\u4e32 **\u300f\u800c\u4e0d\u662f SQL\u6307\u4ee4\u3002\u6b64\u65f6\u5c31\u8981\u900f\u8fc7 PREPARE \u534f\u52a9\u8f6c\u6362\u4e3a PREPARE ID\uff0c\u8fd9\u624d\u662f\u53ef\u4ee5\u4ea4\u4ed8\u6267\u884c\u7684\u90e8\u5206\u3002<\/p>\n

    PREPARE query_prepare FROM ls_sql<\/p>\n

    DECLARE<\/h4>\n

    \u5ba3\u544a\uff0c\u4e5f\u5c31\u662f\u544a\u77e5\u6570\u636e\u5e93\u8981\u6267\u884c\u7684\u6307\u4ee4\u4e3a\u4f55\u3002\u4ee5\u6570\u636e\u5e93\u7684\u89d2\u5ea6\u6765\u8bf4\uff0c\u5373\u662f\u901a\u77e5\u6570\u636e\u5e93\u5c06\u8981\u6267\u884c\u7684SQL\u6307\u4ee4\uff0c\u8ba9\u6570\u636e\u5e93\u5f00\u59cb\u8fdb\u884c\u300e\u8bed\u6cd5\u68c0\u67e5\u3001\u786c\u89e3\u6790hard parse\u300f\u3002\u5728 CURSOR \u4e2d\uff0c\u5fc5\u987b\u544a\u8bc9\u6570\u636e\u5e93\uff0c\u7a0d\u540e\u662f\u4e00\u7b14\u4e00\u7b14\u8f93\u51fa\u8fd8\u662f\u8fde\u7eed\u4e0d\u65ad\u7684\u8f93\u51fa\u3002<\/p>\n

    DECLARE query_declare CURSOR [WITH HOLD] FOR query_declare<\/p>\n

    \u4e0a\u8ff0\u8303\u4f8b\uff0c\u5982\u679c\u52a0\u4e0a WITH HOLD\u5c31\u4f1a\u662f\u4e00\u7b14\u4e00\u7b14\u7684\u8f93\u51fa\u3002
    \n\u9000\u56de\u5230\u4e0a\u4e00\u6bb5 PREPARE\uff0c\u5982\u679c\u6574\u4e2a SQL\u6307\u4ee4\u5e76\u6ca1\u6709\u4e00\u5806\u53d8\u91cf\u7ec4\u88c5\uff0c\u800c\u662f\u4e00\u4e2a\u76f4\u63a5\u64b0\u5199\u7684 SQL \u6307\u4ee4\uff0c\u53ef\u4ee5\u7701\u7565 PREPARE\u76f4\u63a5\u505a DECLARE \u5417\uff1f\u53ef\u4ee5\u7684\uff0c\u5c06 FOR prepare id \u6539\u4e3a FROM sql_statement \u5c31\u53ef\u4ee5\u4e86\u3002<\/p>\n

    FETCH\/FOREACH<\/h4>\n

    \u6700\u7ec8\u900f\u8fc7 FETCH\/FOREACH \u5c31\u53ef\u4ee5\u53d6\u5f97\u6570\u636e\u3002\u5bf9\u4e86\uff0c\u82e5\u6709\u53c2\u6570\u662f\u5728 SQL\u6307\u4ee4\u8ba2\u5b9a\u65f6\u6240\u4e0d\u77e5\u9053\u7684\uff0c\u53ef\u4ee5\u4f7f\u7528 ? \u4f20\u9012\u3002<\/p>\n

    \u5176\u5b9e\u6700\u8be5\u7528 ? \u4f20\u9012\u7684\u662f\u300e\u65e5\u671f\/\u65f6\u95f4\u300f\uff0c\u56e0\u4e3a\u5982\u679c\u7528\u7ec4\u5b57\u7b26\u4e32\u7684\u65b9\u5f0f\u4f20\u5165\uff0c\u5fc5\u987b\u4fdd\u8bc1\u5728\u6267\u884c\u5f53\u4e0b\u53d6\u5f97\u7684\u53d8\u91cf\u5448\u73b0\u683c\u5f0f\u4e0e db \u9700\u6c42\u683c\u5f0f\u662f\u76f8\u7b26\u7684\uff0c\u8fd9\u5e76\u4e0d\u5bb9\u6613\u4e14\u4e0d\u597d\u9664\u9519\uff0c\u56e0\u6b64\u65e5\u671f\u6570\u636e\u7684\u4f20\u5165\uff0c\u591a\u5efa\u8bae\u4f7f\u7528 ? \u8fdb\u884c<\/p>\n

    \u5b8c\u6574\u7684 QBE\u8f6c\u67e5\u8be2\u8303\u4f8b
    \n    https:\/\/4js.com\/online_documentation\/fjs-fgl-manual-html\/#fgl-topics\/c_fgl_result_sets_DECLARE.html<\/a><\/p>\n

    SQL BLOCK<\/h3>\n

    \u5728 DECLARE \u6bb5\u843d\u4e2d\uff0c\u6709\u8c08\u5230\u4f7f\u7528DECLARE \u65f6\uff0c\u4f1a\u5c06 \u300eSQL\u5b57\u7b26\u4e32\u300f\u4f20\u5165\u6570\u636e\u5e93\u5185\u505a\u786c\u89e3\u6790\u3002\u6240\u4ee5\uff0c\u8fd9\u4e2a\u5b57\u7b26\u4e32\u60f3\u5fc5\u300e\u9700\u8981\u7b26\u5408\u6570\u636e\u5e93\u80fd\u770b\u61c2\u7684\u8bed\u6cd5<\/strong>\u300f !!<\/p>\n

    \u4e3e\u4f8b\u6765\u8bf4\uff0cGenero\u9ed8\u8ba4\u4f7f\u7528INFORMIX\u8bed\u6cd5\u65f6\uff0c\u800c\u53c8\u6211\u4eec\u73af\u5883\u94fe\u63a5\u7684\u662f ORACLE\u6570\u636e\u5e93\uff0c\u90a3\u5728\u505a DECLARE \u7684\u65f6\u5019\uff0c\u5c31\u8981\u7528 ORACLE\u7684\u8bed\u6cd5\u5199\u3001\u7528ORACLE\u7684 function\u3001\u53d8\u91cf\u7b49\u3002\u5426\u5219 ORACLE \u770b\u5230 INFORMIX\u4e13\u7528\u7684\u8bed\u6cd5\uff0c\u4e00\u5b9a\u4f1a\u56e0\u4e3a\u8ba4\u4e0d\u5f97\u800c\u51fa\u9519\u3002<\/p>\n

    \u53c8\uff0c\u9664\u4e86 DECLARE \u4e4b\u5916\uff0c\u53e6\u5916\u5728 FGL\u4e2d\uff0c\u4e3a\u4e86\u548c i4GL \u517c\u5bb9\uff0c\u8fd8\u652f\u6301\u4e0b\u5217\u8bed\u6cd5<\/p>\n

    SQL<\/p>\n

    SELECT COUNT(1) INTO $\u53d8\u6570 FROM test<\/p>\n

    END SQL<\/p>\n

    \u4e2d\u95f4\u7684\u53d8\u91cf\u5c31\u662f FGL\u7684\u53d8\u91cf\u3002\u900f\u8fc7\u8fd9\u6837\u7684\u65b9\u5f0f\uff0c\u4f1a\u6bd4\u5230\u5904\u8981\u505a DECLARE \u6765\u7684\u65b9\u4fbf\u4e9b\u3002<\/p>\n

    \u7279\u522b\u6ce8\u8bb0<\/p>\n

      \n
    1. DECLARE-FETCH\/FOREACH \u53ef\u4ee5\u5206\u6563\u5728\u4e0d\u540cfunction\u4e2d\uff0c\u4f46\u662f\u300e\u7269\u7406\u4e0a\u300f\u7f16\u8bd1\u5230FETCH\/FOREACH \u6bb5\u843d\u65f6\uff0c\u4e00\u5b9a\u8981\u5148\u300e\u7f16\u8bd1\u8fc7DECLARE\u300f (\u4e5f\u5c31\u662f\u8bf4 DECLARE \u6240\u5728\u884c\u53f7\u8981\u5c0f\u4e8e FETCH\/FOREACH\u7684\u884c\u53f7!!!)<\/li>\n
    2. PREPARE id \/ DECLARE id \u90fd\u5c5e\u4e8e\u300e\u6a21\u5757\u53d8\u91cf\u300f\uff0c\u5355\u4e004GL\u6863\u6848\u5185\u4e0d\u53ef\u91cd\u590d<\/li>\n<\/ol>\n

      \u5e0c\u671b\u900f\u8fc7\u672c\u6bb5\u7684\u8bb2\u89e3\uff0c\u80fd\u8ba9\u5927\u5bb6\u66f4\u7406\u89e3\u6293\u53d6\u6570\u636e\u7684\u65b9\u6cd5\u3002\u4e5f\u5b8c\u6210\u56db\u9879\u4ea4\u8c08\u6307\u4ee4\u7684\u4ecb\u7ecd\u3002<\/p>\n

      \u8f6c\u8f7d\u8bf7\u6ce8\u660e\uff1a\u8d6b\u975e\u57df<\/a> » [day21] FGL \u7a0b\u5e8f\u5f00\u53d1(4) – \u67e5\u8be2\u6761\u4ef6\u8f93\u5165(QBE: Query By Example)<\/a><\/p>","protected":false},"excerpt":{"rendered":"

      \u6587\u7ae0\u6765\u81ea\uff1aiT \u90a6\u5e6b\u5fd9::\u4e00\u8d77\u5e6b\u5fd9\u89e3\u6c7a\u96e3\u984c\uff0c\u62ef\u6551 IT \u4eba\u7684\u4e00\u5929 (ithome.com.tw) [day21] FGL \u7a0b\u5e8f\u5f00\u53d1(4) – \u67e5\u8be2\u6761\u4ef6\u8f93\u5165(QBE: Query By Example) \u8fd9\u4e2a\u7ae0\u8282\u4e2d\uff0c\u6211\u4eec\u63a2\u8ba8\u56db\u7c7b\u67e5\u8be2\u6307\u4ee4\u4e2d\u5269 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[490,26],"tags":[406,642,407],"class_list":["post-8489","post","type-post","status-publish","format-standard","hentry","category-490","category-4gl","tag-construct","tag-642","tag-407"],"_links":{"self":[{"href":"https:\/\/www.hefeiyu.com\/index.php?rest_route=\/wp\/v2\/posts\/8489","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.hefeiyu.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.hefeiyu.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.hefeiyu.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.hefeiyu.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=8489"}],"version-history":[{"count":2,"href":"https:\/\/www.hefeiyu.com\/index.php?rest_route=\/wp\/v2\/posts\/8489\/revisions"}],"predecessor-version":[{"id":8526,"href":"https:\/\/www.hefeiyu.com\/index.php?rest_route=\/wp\/v2\/posts\/8489\/revisions\/8526"}],"wp:attachment":[{"href":"https:\/\/www.hefeiyu.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=8489"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.hefeiyu.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=8489"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.hefeiyu.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=8489"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}