{"id":14212,"date":"2023-12-04T00:50:39","date_gmt":"2023-12-03T16:50:39","guid":{"rendered":"https:\/\/wx.kaifamiao.info\/?p=14212"},"modified":"2023-12-04T00:52:27","modified_gmt":"2023-12-03T16:52:27","slug":"mybatis-shi-xian-yi-dui-duo-you-ji-zhong-fang-shi","status":"publish","type":"post","link":"http:\/\/wx.kaifamiao.info\/index.php\/2023\/12\/04\/mybatis-shi-xian-yi-dui-duo-you-ji-zhong-fang-shi\/","title":{"rendered":"MyBatis \u5b9e\u73b0\u4e00\u5bf9\u591a\u6709\u51e0\u79cd\u65b9\u5f0f\uff0c\u600e\u4e48\u64cd\u4f5c\u7684\uff1f"},"content":{"rendered":"

MyBatis \u5b9e\u73b0\u4e00\u5bf9\u591a\u5173\u8054\u67e5\u8be2\u6709\u51e0\u79cd\u65b9\u5f0f\uff0c\u4e3b\u8981\u6709\u4e24\u79cd\u5e38\u7528\u7684\u65b9\u5f0f\uff1a\u5d4c\u5957\u67e5\u8be2\u548c\u5d4c\u5957\u7ed3\u679c\u3002<\/p>\n

1. \u5d4c\u5957\u67e5\u8be2\uff08Nested Queries\uff09<\/h3>\n

\u8fd9\u79cd\u65b9\u5f0f\u662f\u901a\u8fc7\u5728\u5916\u5c42\u67e5\u8be2\u4e2d\u8c03\u7528\u5185\u5c42\u67e5\u8be2\u6765\u5b9e\u73b0\u4e00\u5bf9\u591a\u5173\u8054\u67e5\u8be2\u3002<\/p>\n

\u6b65\u9aa4\uff1a<\/h4>\n
    \n
  1. \u5b9a\u4e49\u4e24\u4e2a SQL \u67e5\u8be2\u8bed\u53e5\uff1a<\/strong> \u4e00\u4e2a\u67e5\u8be2\u4e3b\u5bf9\u8c61\uff0c\u53e6\u4e00\u4e2a\u67e5\u8be2\u5173\u8054\u5bf9\u8c61\u3002<\/p>\n<\/li>\n
  2. \n

    \u4f7f\u7528 <collection><\/code> \u5143\u7d20\u8fdb\u884c\u5173\u8054\u6620\u5c04\uff1a<\/strong> \u5728\u4e3b\u67e5\u8be2\u7684 ResultMap \u4e2d\u4f7f\u7528 <collection><\/code> \u5143\u7d20\u6765\u6620\u5c04\u5173\u8054\u5bf9\u8c61\uff0c\u5e76\u6307\u5b9a\u5173\u8054\u67e5\u8be2\u8bed\u53e5\u3002<\/p>\n<\/li>\n<\/ol>\n

    \u793a\u4f8b\uff1a<\/p>\n

    <!-- \u4e3b\u5bf9\u8c61\u67e5\u8be2 -->\n<select id=\"getBlogById\" resultMap=\"blogResult\">\n    SELECT * FROM blogs WHERE blog_id = #{blogId}\n<\/select>\n\n<!-- \u5173\u8054\u5bf9\u8c61\u67e5\u8be2 -->\n<select id=\"getPostsByBlogId\" resultMap=\"postResult\">\n    SELECT * FROM posts WHERE blog_id = #{blogId}\n<\/select>\n\n<!-- \u4e3b\u5bf9\u8c61 ResultMap -->\n<resultMap id=\"blogResult\" type=\"Blog\">\n    <id property=\"id\" column=\"blog_id\"\/>\n    <result property=\"title\" column=\"blog_title\"\/>\n    <!-- \u5d4c\u5957\u67e5\u8be2\u5173\u8054\u5bf9\u8c61 -->\n    <collection property=\"posts\" ofType=\"Post\" select=\"getPostsByBlogId\"\/>\n<\/resultMap>\n<\/code><\/pre>\n
    2. \u5d4c\u5957\u7ed3\u679c\uff08Nested Results\uff09<\/h3>\n
    \u8fd9\u79cd\u65b9\u5f0f\u662f\u5728\u5355\u4e2a\u67e5\u8be2\u4e2d\u4f7f\u7528\u5d4c\u5957\u7684 <resultMap><\/code> \u6765\u76f4\u63a5\u83b7\u53d6\u5173\u8054\u5bf9\u8c61\u3002<\/p>\n
    \u6b65\u9aa4\uff1a<\/h4>\n
      \n
    1. \u5b9a\u4e49\u5355\u4e2a SQL \u67e5\u8be2\u8bed\u53e5\uff1a<\/strong> \u5728\u67e5\u8be2\u4e2d\u5305\u542b\u5173\u8054\u5bf9\u8c61\u7684\u5b57\u6bb5\uff0c\u5e76\u4f7f\u7528\u5d4c\u5957\u7684 <resultMap><\/code> \u6765\u6620\u5c04\u5173\u8054\u5bf9\u8c61\u3002<\/li>\n<\/ol>\n
      \u793a\u4f8b\uff1a<\/p>\n
      <!-- \u5355\u4e2a\u67e5\u8be2\u8bed\u53e5\uff0c\u540c\u65f6\u83b7\u53d6\u4e3b\u5bf9\u8c61\u548c\u5173\u8054\u5bf9\u8c61 -->\n<select id=\"getBlogWithPosts\" resultMap=\"blogWithPostsResult\">\n    SELECT b.blog_id, b.blog_title, p.post_id, p.post_content\n    FROM blogs b LEFT JOIN posts p ON b.blog_id = p.blog_id\n    WHERE b.blog_id = #{blogId}\n<\/select>\n\n<!-- \u5d4c\u5957\u7684 ResultMap -->\n<resultMap id=\"blogWithPostsResult\" type=\"Blog\">\n    <id property=\"id\" column=\"blog_id\"\/>\n    <result property=\"title\" column=\"blog_title\"\/>\n    <!-- \u5d4c\u5957\u5173\u8054\u5bf9\u8c61\u7684 ResultMap -->\n    <association property=\"posts\" javaType=\"java.util.List\" resultMap=\"postResult\"\/>\n<\/resultMap>\n<\/code><\/pre>\n
      \u8fd9\u4e24\u79cd\u65b9\u5f0f\u5747\u80fd\u5b9e\u73b0\u4e00\u5bf9\u591a\u5173\u8054\u67e5\u8be2\uff0c\u53ef\u4ee5\u6839\u636e\u5b9e\u9645\u60c5\u51b5\u9009\u62e9\u66f4\u9002\u5408\u7684\u65b9\u5f0f\u6765\u67e5\u8be2\u5e76\u6620\u5c04\u4e00\u5bf9\u591a\u5173\u8054\u7684\u5bf9\u8c61\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
      MyBatis \u5b9e\u73b0\u4e00\u5bf9\u591a\u5173\u8054\u67e5\u8be2\u6709\u51e0\u79cd\u65b9\u5f0f\uff0c\u4e3b\u8981\u6709\u4e24\u79cd\u5e38\u7528\u7684\u65b9\u5f0f\uff1a\u5d4c\u5957\u67e5\u8be2\u548c\u5d4c\u5957\u7ed3\u679c\u3002 1. \u5d4c\u5957\u67e5\u8be2\uff08Ne […]<\/p>\n","protected":false},"author":11,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[113],"tags":[],"class_list":["post-14212","post","type-post","status-publish","format-standard","hentry","category-mybatis"],"_links":{"self":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/14212","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/users\/11"}],"replies":[{"embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/comments?post=14212"}],"version-history":[{"count":1,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/14212\/revisions"}],"predecessor-version":[{"id":14213,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/14212\/revisions\/14213"}],"wp:attachment":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/media?parent=14212"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/categories?post=14212"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/tags?post=14212"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}