(window.webpackJsonp=window.webpackJsonp||[]).push([[387],{955:function(t,s,a){"use strict";a.r(s);var n=a(70),e=Object(n.a)({},(function(){var t=this,s=t.$createElement,a=t._self._c||s;return a("ContentSlotsDistributor",{attrs:{"slot-key":t.$parent.slotKey}},[a("h1",{attrs:{id:"用户定义函数-udf"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#用户定义函数-udf"}},[t._v("#")]),t._v(" 用户定义函数(UDF)")]),t._v(" "),a("p",[t._v("UDF（User Defined Function）即用户自定义函数。IoTDB提供多种内建函数来满足您的计算需求，同时您还可以通过创建自定义函数来满足更多的计算需求。")]),t._v(" "),a("p",[t._v("根据此文档，您将会很快学会UDF的编写、注册、使用等操作。")]),t._v(" "),a("h2",{attrs:{id:"udf类型"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#udf类型"}},[t._v("#")]),t._v(" UDF类型")]),t._v(" "),a("p",[t._v("IoTDB 支持两种类型的 UDF 函数，如下表所示。")]),t._v(" "),a("table",[a("thead",[a("tr",[a("th",[t._v("UDF 分类")]),t._v(" "),a("th",[t._v("描述")])])]),t._v(" "),a("tbody",[a("tr",[a("td",[t._v("UDTF（User Defined Timeseries Generating Function）")]),t._v(" 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"),a("h2",{attrs:{id:"udf卸载"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#udf卸载"}},[t._v("#")]),t._v(" UDF卸载")]),t._v(" "),a("p",[t._v("卸载UDF的SQL语法如下：")]),t._v(" "),a("div",{staticClass:"language-sql line-numbers-mode"},[a("pre",{pre:!0,attrs:{class:"language-sql"}},[a("code",[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("DROP")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("FUNCTION")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<")]),t._v("UDF"),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("-")]),t._v("NAME"),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v(">")]),t._v("\n")])]),t._v(" "),a("div",{staticClass:"line-numbers-wrapper"},[a("span",{staticClass:"line-number"},[t._v("1")]),a("br")])]),a("p",[t._v("可以通过如下SQL语句卸载上面例子中的UDF：")]),t._v(" "),a("div",{staticClass:"language-sql line-numbers-mode"},[a("pre",{pre:!0,attrs:{class:"language-sql"}},[a("code",[a("span",{pre:!0,attrs:{class:"token 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"),a("p",[t._v("假定现在有时间序列 "),a("code",[t._v("root.sg.d1.s1")]),t._v("和 "),a("code",[t._v("root.sg.d1.s2")]),t._v("。")]),t._v(" "),a("ul",[a("li",[a("strong",[t._v("执行"),a("code",[t._v("SELECT example(*) from root.sg.d1")])])])]),t._v(" "),a("p",[t._v("那么结果集中将包括"),a("code",[t._v("example(root.sg.d1.s1)")]),t._v("和"),a("code",[t._v("example(root.sg.d1.s2)")]),t._v("的结果。")]),t._v(" "),a("ul",[a("li",[a("strong",[t._v("执行"),a("code",[t._v("SELECT example(s1, *) from root.sg.d1")])])])]),t._v(" "),a("p",[t._v("那么结果集中将包括"),a("code",[t._v("example(root.sg.d1.s1, root.sg.d1.s1)")]),t._v("和"),a("code",[t._v("example(root.sg.d1.s1, root.sg.d1.s2)")]),t._v("的结果。")]),t._v(" "),a("ul",[a("li",[a("strong",[t._v("执行"),a("code",[t._v("SELECT example(*, *) from root.sg.d1")])])])]),t._v(" "),a("p",[t._v("那么结果集中将包括"),a("code",[t._v("example(root.sg.d1.s1, root.sg.d1.s1)")]),t._v("，"),a("code",[t._v("example(root.sg.d1.s2, root.sg.d1.s1)")]),t._v("，"),a("code",[t._v("example(root.sg.d1.s1, 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"),a("code",[t._v("dev@iotdb.apache.org")]),t._v(" 或直接创建 ISSUE 发起讨论。")])]),t._v(" "),a("li",[a("p",[t._v("UDF 已经完成测试，且能够正常运行在用户的生产环境中。")])])]),t._v(" "),a("h3",{attrs:{id:"贡献清单"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#贡献清单"}},[t._v("#")]),t._v(" 贡献清单")]),t._v(" "),a("ol",[a("li",[t._v("UDF 的源代码")]),t._v(" "),a("li",[t._v("UDF 的测试用例")]),t._v(" "),a("li",[t._v("UDF 的使用说明")])]),t._v(" "),a("h4",{attrs:{id:"源代码"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#源代码"}},[t._v("#")]),t._v(" 源代码")]),t._v(" "),a("ol",[a("li",[t._v("在"),a("code",[t._v("src/main/java/org/apache/iotdb/db/query/udf/builtin")]),t._v("或者它的子文件夹中创建 UDF 主类和相关的辅助类。")]),t._v(" "),a("li",[t._v("在"),a("code",[t._v("src/main/java/org/apache/iotdb/db/query/udf/builtin/BuiltinFunction.java")]),t._v("中注册您编写的 UDF。")])]),t._v(" "),a("h4",{attrs:{id:"测试用例"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#测试用例"}},[t._v("#")]),t._v(" 测试用例")]),t._v(" "),a("p",[t._v("您至少需要为您贡献的 UDF 编写集成测试。")]),t._v(" "),a("p",[t._v("您可以在"),a("code",[t._v("server/src/test/java/org/apache/iotdb/db/integration")]),t._v("中为您贡献的 UDF 新增一个测试类进行测试。")]),t._v(" "),a("h4",{attrs:{id:"使用说明"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#使用说明"}},[t._v("#")]),t._v(" 使用说明")]),t._v(" "),a("p",[t._v("使用说明需要包含：UDF 的名称、UDF的作用、执行函数必须的属性参数、函数的适用的场景以及使用示例等。")]),t._v(" "),a("p",[t._v("使用说明需包含中英文两个版本。应分别在 "),a("code",[t._v("docs/zh/UserGuide/Operation Manual/DML Data Manipulation Language.md")]),t._v(" 和 "),a("code",[t._v("docs/UserGuide/Operation Manual/DML Data Manipulation Language.md")]),t._v(" 中新增使用说明。")]),t._v(" "),a("h3",{attrs:{id:"提交pr"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#提交pr"}},[t._v("#")]),t._v(" 提交PR")]),t._v(" "),a("p",[t._v("当您准备好源代码、测试用例和使用说明后，就可以将 UDF 贡献到 IoTDB 社区了。在 "),a("a",{attrs:{href:"https://github.com/apache/iotdb",target:"_blank",rel:"noopener noreferrer"}},[t._v("Github"),a("OutboundLink")],1),t._v(" 上面提交 Pull Request (PR) 即可。具体提交方式见："),a("a",{attrs:{href:"https://iotdb.apache.org/Development/HowToCommit.html",target:"_blank",rel:"noopener noreferrer"}},[t._v("Pull Request Guide"),a("OutboundLink")],1),t._v("。")]),t._v(" "),a("p",[t._v("当 PR 评审通过并被合并后，您的 UDF 就已经贡献给 IoTDB 社区了！")]),t._v(" "),a("h2",{attrs:{id:"已知的udf库实现"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#已知的udf库实现"}},[t._v("#")]),t._v(" 已知的UDF库实现")]),t._v(" "),a("ul",[a("li",[a("a",{attrs:{href:"https://thulab.github.io/iotdb-quality",target:"_blank",rel:"noopener noreferrer"}},[t._v("IoTDB-Quality"),a("OutboundLink")],1),t._v("，一个关于数据质量的UDF库实现，包括数据画像、数据质量评估与修复等一系列函数。")])]),t._v(" "),a("h2",{attrs:{id:"q-a"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#q-a"}},[t._v("#")]),t._v(" Q&A")]),t._v(" "),a("p",[a("strong",[t._v("Q1: 如何修改已经注册的UDF？")])]),t._v(" "),a("p",[t._v("A1: 假设UDF的名称为"),a("code",[t._v("example")]),t._v("，全类名为"),a("code",[t._v("org.apache.iotdb.udf.UDTFExample")]),t._v("，由"),a("code",[t._v("example.jar")]),t._v("引入")]),t._v(" "),a("ol",[a("li",[t._v("首先卸载已经注册的"),a("code",[t._v("example")]),t._v("函数，执行"),a("code",[t._v("DROP FUNCTION example")])]),t._v(" "),a("li",[t._v("删除 "),a("code",[t._v("iotdb-server-0.13.0-SNAPSHOT/ext/udf")]),t._v(" 目录下的"),a("code",[t._v("example.jar")])]),t._v(" "),a("li",[t._v("修改"),a("code",[t._v("org.apache.iotdb.udf.UDTFExample")]),t._v("中的逻辑，重新打包，JAR包的名字可以仍然为"),a("code",[t._v("example.jar")])]),t._v(" "),a("li",[t._v("将新的JAR包上传至 "),a("code",[t._v("iotdb-server-0.13.0-SNAPSHOT/ext/udf")]),t._v(" 目录下")]),t._v(" "),a("li",[t._v("装载新的UDF，执行"),a("code",[t._v('CREATE FUNCTION example AS "org.apache.iotdb.udf.UDTFExample"')])])])])}),[],!1,null,null,null);s.default=e.exports}}]);