Laravel 5.7执行几次SQL查询？

Question

在Laracasts.com上学习Laravel 5.7，它展示了如何使用Eloquent模型对象从数据库中获取1:N关系记录，如下所示。

// One SQL query is being executed here.
$project = Project::first();

// Another SQL query must be executed here to be abled to count the tasks. Right?
if ($project->tasks->count()) {

    // Is another SQL query being executed here to fetch the task's  records related to the project? 
    foreach ($project->tasks as $task) {

         echo $task->name;
    }
}

使用上述方法已执行了多少个SQL查询？ 我不确定正在执行2或3个SQL查询。

Answer 1

您正在寻找的是DB :: enableQueryLog / DB::getQueryLog ：

Laravel可以选择将所有针对当前请求运行的查询登录到内存中。 请注意，在某些情况下（例如，插入大量行时），这可能导致应用程序使用过多的内存。 要启用日志，可以使用enableQueryLog method: DB::connection()->enableQueryLog();

\DB::enableQueryLog();

// One SQL query is being executed here.
$project = Project::first();

// Another SQL query must be executed here to be abled to count the tasks. Right?
if ($project->tasks->count()) {

    // Is another SQL query being executed here to fetch the task's  records related to the project?
    foreach ($project->tasks as $task) {

        echo $task->name;
    }
}

# queries so far
\DB::getQueryLog();

• 监听查询事件
• 查询记录