laravel5.1框架model類查詢實現

laravel框架model類查詢實現：

User::where(['uid'=8])->get();

User類繼承自Model類：Illuminate\Database\Eloquent\Model

 

當User類靜態調用where方法時，自動調用了Model里的魔術方法：

public static function __callStatic($method, $parameters)
{
    $instance = new static; //這里的$instance就是User類的實例對象

    return call_user_func_array([$instance, $method], $parameters);
}

 

 相當於調用了user對象的where方法，這時就又調用了魔術方法：

public function __call($method, $parameters)
{
    if (in_array($method, ['increment', 'decrement'])) {
        return call_user_func_array([$this, $method], $parameters);
    }

    $query = $this->newQuery(); //返回Illuminate\Database\Eloquent\Builder對象

    return call_user_func_array([$query, $method], $parameters);
}

 

相當於調用Illuminate\Database\Eloquent\Builder對象里的where方法和get方法，這兩個方法里其實

其實是封裝調用了Illuminate\Database\Query\Builder對象里的where方法和get方法->get方法里調用了runselect方法

runSelect方法:

/**
 * Run the query as a "select" statement against the connection.
 *
 * @return array
 */
protected function runSelect()
{
    return $this->connection->select($this->toSql(), $this->getBindings(), ! $this->useWritePdo); //調用connection 對象的select方法
}

 
再看connection對象是怎么傳到Illuminate\Database\Eloquent\Builder類實例里的：

Model類的newQuery方法：

/**
 * Get a new query builder for the model's table.
 *
 * @return \Illuminate\Database\Eloquent\Builder
 */
public function newQuery()
{
    $builder = $this->newQueryWithoutScopes();

    return $this->applyGlobalScopes($builder);
}

 

Model類的newQueryWithoutScopes方法：

/**
 * Get a new query builder that doesn't have any global scopes.
 *
 * @return \Illuminate\Database\Eloquent\Builder|static
 */
public function newQueryWithoutScopes()
{
    $builder = $this->newEloquentBuilder(
        $this->newBaseQueryBuilder() //這個方法返回
    );

    // Once we have the query builders, we will set the model instances so the
    // builder can easily access any information it may need from the model
    // while it is constructing and executing various queries against it.
    return $builder->setModel($this)->with($this->with);
}

 

Model類的newBaseQueryBuilder方法實現

/**
 * Get a new query builder instance for the connection.
 *
 * @return \Illuminate\Database\Query\Builder
 */
protected function newBaseQueryBuilder()
{
    $conn = $this->getConnection(); \\連接數據庫並返回connection對象

    $grammar = $conn->getQueryGrammar();

    return new QueryBuilder($conn, $grammar, $conn->getPostProcessor()); //Illuminate\Database\Query\Builder

}

 

Model類的$resolver屬性(連接解析器)的設定是通過

Illuminate\Database\DatabaseServiceProvider 里的boot方法設置的

這樣Model類的getConnection方法實際調用的DatabaseManager類的connection方法，返回connection類實例

如何創建的數據庫連接：

Model類getConnection方法->DatabaseManager類connection方法->

->ConnectionFactory類的createSingleConnection()

 

/**
 * Create a single database connection instance.
 *
 * @param  array  $config
 * @return \Illuminate\Database\Connection
 */
protected function createSingleConnection(array $config)
{
    //創建連接器對象並連接數據庫返回pdo對象
    $pdo = $this->createConnector($config)->connect($config);
    //傳入PDO對象、並返回connection對象，connection對象負責查詢數據庫
    return $this->createConnection($config['driver'], $pdo, $config['database'], $config['prefix'], $config); 

}