Laravel中tosql()是如何返回sql

前言

1. laravel version 5.5 

2. 关键字sql解析的代码，我就不上了。有兴趣的童鞋，能够去Illuminate\Database\Query\Grammars\Grammar观望，我也就简单说下，Laravel的主体思路。

源码

首先找到tosql()方法所在的位置，Illuminate\Database\Query\Builder：

/** * Get the SQL representation of the query. * * @return string */
    public function toSql() { return $this->grammar->compileSelect($this); }

接着，去 Illuminate\Database\Query\Grammars\Grammar

/**
     * The components that make up a select clause.
     *  关键字数组，用于下面的根据对应关键字拼接对应方法
     * @var array
     */
    protected $selectComponents = [
        'aggregate',
        'columns',
        'from',
        'joins',
        'wheres',
        'groups',
        'havings',
        'orders',
        'limit',
        'offset',
        'unions',
        'lock',
    ];

 

 /** * Compile a select query into SQL. * * @param \Illuminate\Database\Query\Builder $query * @return string */
    public function compileSelect(Builder $query) { // If the query does not have any columns set, we'll set the columns to the // * character to just get all of the columns from the database. Then we // can build the query and concatenate all the pieces together as one.
        $original = $query->columns; if (is_null($query->columns)) { $query->columns = ['*']; } // To compile the query, we'll spin through each component of the query and // see if that component exists. If it does we'll just call the compiler // function for the component which is responsible for making the SQL.
　　　　　// 然鹅，最主体的方法就在这里。
        $sql = trim($this->concatenate( $this->compileComponents($query)) ); $query->columns = $original; return $sql; }
　　　　

 /** * Concatenate an array of segments, removing empties. * * @param array $segments * @return string */
    protected function concatenate($segments) {
　　　　　// 将空值过滤，而且转换为一个字符串，返回。（也就是最终返回的sql） return implode(' ', array_filter($segments, function ($value) { return (string) $value !== ''; })); }

/** * Compile the components necessary for a select clause. * * @param \Illuminate\Database\Query\Builder $query * @return array */
    protected function compileComponents(Builder $query) { $sql = []; 　　　　　// laravel 会根据sql的关键字，for循环出一个sql数组 foreach ($this->selectComponents as $component) { // To compile the query, we'll spin through each component of the query and // see if that component exists. If it does we'll just call the compiler // function for the component which is responsible for making the SQL.
            if (! is_null($query->$component)) { $method = 'compile'.ucfirst($component); $sql[$component] = $this->$method($query, $query->$component); } } return $sql;  }

 

总结

我我的也就是，简略的经过表象的源码分析下laravle的toSql()如何返回sql而已，还没有研究更为深透。

为何开个博文来记录呢？由于，最近一直在看laravel的源码，以为这种思想真的很新颖！！！

共勉~~~