didong
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owl-admin


			
				
					
						
						
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            <blockquote>
<p>以下工具类库，默认基于laravel框架</p>
</blockquote>
<blockquote>
<p>开始开发前，每个项目参与者都必须对laravel、dcat中的一些模块或概念有个基本的认识。否则将无法有效提供AI提示词，则无法加快研发效率。 要求每个人在业余时间对官方文档提供的每一个功能点，做一个开发和测试，这样建立基本的认识。</p>
</blockquote>
<h4 id="1-事务处理">1. 事务处理</h4>
<h5 id="场景说明">场景说明</h5>
<ul>
<li>
<p><strong>串行化 (SERIALIZABLE)</strong>：适用于需要严格事务隔离的场景，例如银行转账，确保事务完全隔离，避免所有并发问题，但可能会影响性能。</p>
</li>
<li>
<p><strong>可重复读 (REPEATABLE READ)</strong>：适用于需要保证在同一事务中多次读取同一数据的一致性的场景，例如库存查询和减少操作，避免在事务过程中数据被其他事务修改。</p>
</li>
<li>
<p><strong>读已提交 (READ COMMITTED)</strong>：适用于大多数需要避免脏读的场景，每次读取都能看到其他事务的最新提交结果，但可能会出现不可重复读和幻读。</p>
</li>
<li>
<p><strong>读未提交 (READ UNCOMMITTED)</strong>：适用于读操作对数据一致性要求不高的场景，允许读取到其他事务未提交的数据，可能会导致脏读、不可重复读和幻读。</p>
</li>
</ul>
<h5 id="用法举例">用法举例</h5>
<pre><code class="language-php"><span class="hljs-comment">// 串行化 (SERIALIZABLE) - 最严格的隔离级别，完全隔离，事务串行执行</span>
<span class="hljs-keyword">use</span> <span class="hljs-title">Illuminate</span>\<span class="hljs-title">Support</span>\<span class="hljs-title">Facades</span>\<span class="hljs-title">DB</span>;

DB::<span class="hljs-title function_ invoke__">transaction</span>(function () {
    <span class="hljs-comment">// 操作1：读取用户A的当前余额</span>
    <span class="hljs-variable">$balanceA</span> = DB::<span class="hljs-title function_ invoke__">table</span>(<span class="hljs-string">&#x27;accounts&#x27;</span>)-&gt;<span class="hljs-title function_ invoke__">where</span>(<span class="hljs-string">&#x27;user_id&#x27;</span>, <span class="hljs-variable">$userIdA</span>)-&gt;<span class="hljs-title function_ invoke__">value</span>(<span class="hljs-string">&#x27;balance&#x27;</span>);

    <span class="hljs-comment">// 操作2：减少用户A的余额</span>
    DB::<span class="hljs-title function_ invoke__">table</span>(<span class="hljs-string">&#x27;accounts&#x27;</span>)-&gt;<span class="hljs-title function_ invoke__">where</span>(<span class="hljs-string">&#x27;user_id&#x27;</span>, <span class="hljs-variable">$userIdA</span>)-&gt;<span class="hljs-title function_ invoke__">decrement</span>(<span class="hljs-string">&#x27;balance&#x27;</span>, <span class="hljs-variable">$amount</span>);

    <span class="hljs-comment">// 操作3：增加用户B的余额</span>
    DB::<span class="hljs-title function_ invoke__">table</span>(<span class="hljs-string">&#x27;accounts&#x27;</span>)-&gt;<span class="hljs-title function_ invoke__">where</span>(<span class="hljs-string">&#x27;user_id&#x27;</span>, <span class="hljs-variable">$userIdB</span>)-&gt;<span class="hljs-title function_ invoke__">increment</span>(<span class="hljs-string">&#x27;balance&#x27;</span>, <span class="hljs-variable">$amount</span>);
}, DB::<span class="hljs-variable constant_">TRANSACTION_SERIALIZABLE</span>);
</code></pre>
<pre><code class="language-php"><span class="hljs-comment">// 可重复读 (REPEATABLE READ) - 保证事务中每次读取结果都相同，避免不可重复读和脏读</span>
<span class="hljs-keyword">use</span> <span class="hljs-title">Illuminate</span>\<span class="hljs-title">Support</span>\<span class="hljs-title">Facades</span>\<span class="hljs-title">DB</span>;

DB::<span class="hljs-title function_ invoke__">transaction</span>(function () {
   
}, DB::<span class="hljs-variable constant_">TRANSACTION_REPEATABLE_READ</span>);
</code></pre>
<pre><code class="language-php"><span class="hljs-comment">// 读已提交 (READ COMMITTED) - 每次读取只能看到其他事务已经提交的数据，避免脏读</span>
<span class="hljs-keyword">use</span> <span class="hljs-title">Illuminate</span>\<span class="hljs-title">Support</span>\<span class="hljs-title">Facades</span>\<span class="hljs-title">DB</span>;

DB::<span class="hljs-title function_ invoke__">transaction</span>(function () {
    
}, DB::<span class="hljs-variable constant_">TRANSACTION_READ_COMMITTED</span>);
</code></pre>
<pre><code class="language-php"><span class="hljs-comment">// 读未提交 (READ UNCOMMITTED) - 最宽松的隔离级别，可能会读取到其他事务未提交的数据（脏读）</span>
<span class="hljs-keyword">use</span> <span class="hljs-title">Illuminate</span>\<span class="hljs-title">Support</span>\<span class="hljs-title">Facades</span>\<span class="hljs-title">DB</span>;

DB::<span class="hljs-title function_ invoke__">transaction</span>(function () {
  
}, DB::<span class="hljs-variable constant_">TRANSACTION_READ_UNCOMMITTED</span>);
</code></pre>
<h5 id="事务嵌套">事务嵌套</h5>
<p>在 Laravel 中，如果你在一个 DB::transaction 回调中调用另一个也使用 DB::transaction 的方法，将会出现以下情况：</p>
<pre><code>嵌套事务：Laravel 支持嵌套事务。当你在事务中调用另一个事务时，Laravel 会使用保存点（Savepoints）来处理嵌套的事务。保存点允许你在事务中设置一个点，之后可以回滚到这个点，而不影响事务中之前的操作。

保存点的创建：对于每个嵌套的事务，Laravel 会创建一个保存点。如果内部事务成功提交，保存点会被释放；如果内部事务失败并回滚，只有内部事务的更改会被回滚到保存点，外部事务的其他操作不受影响。

事务的回滚：如果内部事务中抛出异常，整个内部事务会被回滚到最近的保存点。如果外部事务中抛出异常，整个外部事务（包括所有内部事务）会被回滚。
</code></pre>
<p>下面是一个示例，说明这种情况：</p>
<pre><code class="language-php"><span class="hljs-keyword">use</span> <span class="hljs-title">Illuminate</span>\<span class="hljs-title">Support</span>\<span class="hljs-title">Facades</span>\<span class="hljs-title">DB</span>;

DB::<span class="hljs-title function_ invoke__">transaction</span>(function () {
    <span class="hljs-comment">// 外部事务开始</span>

    <span class="hljs-comment">// 一些数据库操作</span>
    DB::<span class="hljs-title function_ invoke__">table</span>(<span class="hljs-string">&#x27;accounts&#x27;</span>)-&gt;<span class="hljs-title function_ invoke__">insert</span>([...]);

    <span class="hljs-variable language_">$this</span>-&gt;<span class="hljs-title function_ invoke__">nestedTransaction</span>(); <span class="hljs-comment">// 调用包含内部事务的方法</span>

    <span class="hljs-comment">// 更多数据库操作</span>
    DB::<span class="hljs-title function_ invoke__">table</span>(<span class="hljs-string">&#x27;accounts&#x27;</span>)-&gt;<span class="hljs-title function_ invoke__">update</span>([...]);
}, DB::<span class="hljs-variable constant_">TRANSACTION_SERIALIZABLE</span>);

<span class="hljs-comment">// 包含内部事务的方法</span>
<span class="hljs-keyword">protected</span> <span class="hljs-function"><span class="hljs-keyword">function</span> <span class="hljs-title">nestedTransaction</span>(<span class="hljs-params"></span>)
</span>{
    DB::<span class="hljs-title function_ invoke__">transaction</span>(function () {
        <span class="hljs-comment">// 内部事务开始</span>

        <span class="hljs-comment">// 一些数据库操作</span>
        DB::<span class="hljs-title function_ invoke__">table</span>(<span class="hljs-string">&#x27;accounts&#x27;</span>)-&gt;<span class="hljs-title function_ invoke__">insert</span>([...]);

        <span class="hljs-comment">// 假设这里发生了错误，内部事务会回滚</span>
        <span class="hljs-keyword">throw</span> <span class="hljs-keyword">new</span> <span class="hljs-built_in">Exception</span>(<span class="hljs-string">&#x27;Something went wrong!&#x27;</span>);

        <span class="hljs-comment">// 更多数据库操作，如果内部事务成功，这些操作会执行</span>
        DB::<span class="hljs-title function_ invoke__">table</span>(<span class="hljs-string">&#x27;accounts&#x27;</span>)-&gt;<span class="hljs-title function_ invoke__">update</span>([...]);
    }, DB::<span class="hljs-variable constant_">TRANSACTION_SERIALIZABLE</span>);
}
</code></pre>
<blockquote>
<p>在这个例子中，如果 nestedTransaction 方法中的内部事务因为抛出异常而失败，只有内部事务中的操作会被回滚。外部事务中的操作（在调用 nestedTransaction 之前和之后的操作）不会受到影响，除非外部事务本身抛出异常。</p>
</blockquote>
<h4 id="2-队列处理">2. 队列处理</h4>
<p><a href="https://learnku.com/docs/laravel/9.x/queues/12236#0796f7">参考laravel官方文档</a></p>
<h4 id="3-缓存处理">3. 缓存处理</h4>
<p><a href="https://learnku.com/docs/laravel/9.x/redis/12250#e11144">参考laravel官方文档</a></p>
<h4 id="4-日志记录">4. 日志记录</h4>
<p><a href="https://learnku.com/docs/laravel/9.x/logging/12237#0796f7">参考laravel官方文档</a></p>
<h4 id="5-其他请参考官方文档">5. 其他请参考官方文档</h4>
<p><a href="https://learnku.com/docs/laravel/9.x">laravel官方文档</a></p>
<p><a href="https://learnku.com/docs/dcat-admin/2.x">dcat文档</a></p>

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