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import{_ as e,c as n,b as a,o as t}from"./app-C4AeQnH1.js";const i={};function l(r,s){return t(),n("div",null,s[0]||(s[0]=[a(`<h1 id="管理触发器" tabindex="-1"><a class="header-anchor" href="#管理触发器"><span>管理触发器</span></a></h1><p>您可以通过 SQL 语句注册和卸载一个触发器实例，您也可以通过 SQL 语句查询到所有已经注册的触发器。</p><p><strong>我们建议您在注册触发器时停止写入。</strong></p><h2 id="注册触发器" tabindex="-1"><a class="header-anchor" href="#注册触发器"><span>注册触发器</span></a></h2><p>触发器可以注册在任意路径模式上。被注册有触发器的序列将会被触发器侦听，当序列上有数据变动时，触发器中对应的触发方法将会被调用。</p><p>注册一个触发器可以按如下流程进行：</p><ol><li>按照编写触发器章节的说明，实现一个完整的 Trigger 类，假定这个类的全类名为 <code>org.apache.iotdb.trigger.ClusterAlertingExample</code></li><li>将项目打成 JAR 包。</li><li>使用 SQL 语句注册该触发器。注册过程中会仅只会调用一次触发器的 <code>validate</code> 和 <code>onCreate</code> 接口，具体请参考编写触发器章节。</li></ol><p>完整 SQL 语法如下：</p><div class="language-sql line-numbers-mode" data-highlighter="prismjs" data-ext="sql" data-title="sql"><pre><code><span class="line"><span class="token comment">// Create Trigger</span></span>
<span class="line">createTrigger</span>
<span class="line"> : <span class="token keyword">CREATE</span> triggerType <span class="token keyword">TRIGGER</span> triggerName<span class="token operator">=</span>identifier triggerEventClause <span class="token keyword">ON</span> pathPattern <span class="token keyword">AS</span> className<span class="token operator">=</span>STRING_LITERAL uriClause? triggerAttributeClause?</span>
<span class="line"> <span class="token punctuation">;</span></span>
<span class="line"></span>
<span class="line">triggerType</span>
<span class="line"> : STATELESS <span class="token operator">|</span> STATEFUL</span>
<span class="line"> <span class="token punctuation">;</span></span>
<span class="line"></span>
<span class="line">triggerEventClause</span>
<span class="line"> : <span class="token punctuation">(</span>BEFORE <span class="token operator">|</span> <span class="token keyword">AFTER</span><span class="token punctuation">)</span> <span class="token keyword">INSERT</span></span>
<span class="line"> <span class="token punctuation">;</span></span>
<span class="line"></span>
<span class="line">uriClause</span>
<span class="line"> : <span class="token keyword">USING</span> URI uri</span>
<span class="line"> <span class="token punctuation">;</span></span>
<span class="line"></span>
<span class="line">uri</span>
<span class="line"> : STRING_LITERAL</span>
<span class="line"> <span class="token punctuation">;</span></span>
<span class="line"></span>
<span class="line">triggerAttributeClause</span>
<span class="line"> : <span class="token keyword">WITH</span> LR_BRACKET triggerAttribute <span class="token punctuation">(</span>COMMA triggerAttribute<span class="token punctuation">)</span><span class="token operator">*</span> RR_BRACKET</span>
<span class="line"> <span class="token punctuation">;</span></span>
<span class="line"></span>
<span class="line">triggerAttribute</span>
<span class="line"> : <span class="token keyword">key</span><span class="token operator">=</span>attributeKey operator_eq <span class="token keyword">value</span><span class="token operator">=</span>attributeValue</span>
<span class="line"> <span class="token punctuation">;</span></span>
<span class="line"></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>下面对 SQL 语法进行说明，您可以结合使用说明章节进行理解：</p><ul><li>triggerName：触发器 ID，该 ID 是全局唯一的，用于区分不同触发器，大小写敏感。</li><li>triggerType：触发器类型，分为无状态（STATELESS）和有状态（STATEFUL）两类。</li><li>triggerEventClause：触发时机，目前仅支持写入前（BEFORE INSERT）和写入后（AFTER INSERT）两种。</li><li>pathPattern：触发器侦听的路径模式，可以包含通配符 * 和 **。</li><li>className：触发器实现类的类名。</li><li>uriClause：可选项，当不指定该选项时，我们默认 DBA 已经在各个 DataNode 节点的 trigger_root_dir 目录（配置项，默认为 IOTDB_HOME/ext/trigger）下放置好创建该触发器需要的 JAR 包。当指定该选项时，我们会将该 URI 对应的文件资源下载并分发到各 DataNode 的 trigger_root_dir/install 目录下。</li><li>triggerAttributeClause：用于指定触发器实例创建时需要设置的参数，SQL 语法中该部分是可选项。</li></ul><p>下面是一个帮助您理解的 SQL 语句示例：</p><div class="language-sql line-numbers-mode" data-highlighter="prismjs" data-ext="sql" data-title="sql"><pre><code><span class="line"><span class="token keyword">CREATE</span> STATELESS <span class="token keyword">TRIGGER</span> triggerTest</span>
<span class="line">BEFORE <span class="token keyword">INSERT</span></span>
<span class="line"><span class="token keyword">ON</span> root<span class="token punctuation">.</span>sg<span class="token punctuation">.</span><span class="token operator">*</span><span class="token operator">*</span></span>
<span class="line"><span class="token keyword">AS</span> <span class="token string">&#39;org.apache.iotdb.trigger.ClusterAlertingExample&#39;</span></span>
<span class="line"><span class="token keyword">USING</span> URI <span class="token string">&#39;http://jar/ClusterAlertingExample.jar&#39;</span></span>
<span class="line"><span class="token keyword">WITH</span> <span class="token punctuation">(</span></span>
<span class="line"> <span class="token string">&quot;name&quot;</span> <span class="token operator">=</span> <span class="token string">&quot;trigger&quot;</span><span class="token punctuation">,</span></span>
<span class="line"> <span class="token string">&quot;limit&quot;</span> <span class="token operator">=</span> <span class="token string">&quot;100&quot;</span></span>
<span class="line"><span class="token punctuation">)</span></span>
<span class="line"></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>上述 SQL 语句创建了一个名为 triggerTest 的触发器：</p><ul><li>该触发器是无状态的（STATELESS）</li><li>在写入前触发（BEFORE INSERT）</li><li>该触发器侦听路径模式为 <a href="http://root.sg" target="_blank" rel="noopener noreferrer">root.sg</a>.**</li><li>所编写的触发器类名为 org.apache.iotdb.trigger.ClusterAlertingExample</li><li>JAR 包的 URI 为 <a href="http://jar/ClusterAlertingExample.jar" target="_blank" rel="noopener noreferrer">http://jar/ClusterAlertingExample.jar</a></li><li>创建该触发器实例时会传入 name 和 limit 两个参数。</li></ul><h2 id="卸载触发器" tabindex="-1"><a class="header-anchor" href="#卸载触发器"><span>卸载触发器</span></a></h2><p>可以通过指定触发器 ID 的方式卸载触发器，卸载触发器的过程中会且仅会调用一次触发器的 <code>onDrop</code> 接口。</p><p>卸载触发器的 SQL 语法如下：</p><div class="language-sql line-numbers-mode" data-highlighter="prismjs" data-ext="sql" data-title="sql"><pre><code><span class="line"><span class="token comment">// Drop Trigger</span></span>
<span class="line">dropTrigger</span>
<span class="line"> : <span class="token keyword">DROP</span> <span class="token keyword">TRIGGER</span> triggerName<span class="token operator">=</span>identifier</span>
<span class="line"><span class="token punctuation">;</span></span>
<span class="line"></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>下面是示例语句：</p><div class="language-sql line-numbers-mode" data-highlighter="prismjs" data-ext="sql" data-title="sql"><pre><code><span class="line"><span class="token keyword">DROP</span> <span class="token keyword">TRIGGER</span> triggerTest1</span>
<span class="line"></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>上述语句将会卸载 ID 为 triggerTest1 的触发器。</p><h2 id="查询触发器" tabindex="-1"><a class="header-anchor" href="#查询触发器"><span>查询触发器</span></a></h2><p>可以通过 SQL 语句查询集群中存在的触发器的信息。SQL 语法如下：</p><div class="language-sql line-numbers-mode" data-highlighter="prismjs" data-ext="sql" data-title="sql"><pre><code><span class="line"><span class="token keyword">SHOW</span> TRIGGERS</span>
<span class="line"></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>该语句的结果集格式如下：</p><table><thead><tr><th>TriggerName</th><th>Event</th><th>Type</th><th>State</th><th>PathPattern</th><th>ClassName</th><th>NodeId</th></tr></thead><tbody><tr><td>triggerTest1</td><td>BEFORE_INSERT / AFTER_INSERT</td><td>STATELESS / STATEFUL</td><td>INACTIVE / ACTIVE / DROPPING / TRANSFFERING</td><td>root.**</td><td>org.apache.iotdb.trigger.TriggerExample</td><td>ALL(STATELESS) / DATA_NODE_ID(STATEFUL)</td></tr></tbody></table><h2 id="触发器状态说明" tabindex="-1"><a class="header-anchor" href="#触发器状态说明"><span>触发器状态说明</span></a></h2><p>在集群中注册以及卸载触发器的过程中，我们维护了触发器的状态，下面是对这些状态的说明：</p><table><thead><tr><th>状态</th><th>描述</th><th>是否建议写入进行</th></tr></thead><tbody><tr><td>INACTIVE</td><td>执行 <code>CREATE TRIGGER</code> 的中间状态，集群刚在 ConfigNode 上记录该触发器的信息，还未在任何 DataNode 上激活该触发器</td><td>否</td></tr><tr><td>ACTIVE</td><td>执行 <code>CREATE TRIGGE</code> 成功后的状态，集群所有 DataNode 上的该触发器都已经可用</td><td>是</td></tr><tr><td>DROPPING</td><td>执行 <code>DROP TRIGGER</code> 的中间状态，集群正处在卸载该触发器的过程中</td><td>否</td></tr><tr><td>TRANSFERRING</td><td>集群正在进行该触发器实例位置的迁移</td><td>否</td></tr></tbody></table>`,30)]))}const d=e(i,[["render",l],["__file","Trigger-Management.html.vue"]]),o=JSON.parse('{"path":"/zh/UserGuide/V1.0.x/Trigger/Trigger-Management.html","title":"管理触发器","lang":"zh-CN","frontmatter":{"description":"管理触发器 您可以通过 SQL 语句注册和卸载一个触发器实例，您也可以通过 SQL 语句查询到所有已经注册的触发器。 我们建议您在注册触发器时停止写入。 注册触发器 触发器可以注册在任意路径模式上。被注册有触发器的序列将会被触发器侦听，当序列上有数据变动时，触发器中对应的触发方法将会被调用。 注册一个触发器可以按如下流程进行： 按照编写触发器章节的说明...","head":[["link",{"rel":"alternate","hreflang":"en-us","href":"https://iotdb.apache.org/UserGuide/V1.0.x/Trigger/Trigger-Management.html"}],["meta",{"property":"og:url","content":"https://iotdb.apache.org/zh/UserGuide/V1.0.x/Trigger/Trigger-Management.html"}],["meta",{"property":"og:site_name","content":"IoTDB Website"}],["meta",{"property":"og:title","content":"管理触发器"}],["meta",{"property":"og:description","content":"管理触发器 您可以通过 SQL 语句注册和卸载一个触发器实例，您也可以通过 SQL 语句查询到所有已经注册的触发器。 我们建议您在注册触发器时停止写入。 注册触发器 触发器可以注册在任意路径模式上。被注册有触发器的序列将会被触发器侦听，当序列上有数据变动时，触发器中对应的触发方法将会被调用。 注册一个触发器可以按如下流程进行： 按照编写触发器章节的说明..."}],["meta",{"property":"og:type","content":"article"}],["meta",{"property":"og:locale","content":"zh-CN"}],["meta",{"property":"og:locale:alternate","content":"en-US"}],["meta",{"property":"og:updated_time","content":"2023-07-10T03:11:17.000Z"}],["meta",{"property":"article:modified_time","content":"2023-07-10T03:11:17.000Z"}],["script",{"type":"application/ld+json"},"{\\"@context\\":\\"https://schema.org\\",\\"@type\\":\\"Article\\",\\"headline\\":\\"管理触发器\\",\\"image\\":[\\"\\"],\\"dateModified\\":\\"2023-07-10T03:11:17.000Z\\",\\"author\\":[]}"]]},"headers":[{"level":2,"title":"注册触发器","slug":"注册触发器","link":"#注册触发器","children":[]},{"level":2,"title":"卸载触发器","slug":"卸载触发器","link":"#卸载触发器","children":[]},{"level":2,"title":"查询触发器","slug":"查询触发器","link":"#查询触发器","children":[]},{"level":2,"title":"触发器状态说明","slug":"触发器状态说明","link":"#触发器状态说明","children":[]}],"git":{"createdTime":1688958677000,"updatedTime":1688958677000,"contributors":[{"name":"CritasWang","email":"critas@outlook.com","commits":1}]},"readingTime":{"minutes":3.63,"words":1089},"filePathRelative":"zh/UserGuide/V1.0.x/Trigger/Trigger-Management.md","localizedDate":"2023年7月10日","autoDesc":true}');export{d as comp,o as data};