【Laravel3.0.0源码阅读分析】数据库连接类connection.php
作者：互联网
<?php namespace Laravel\Database; use PDO, PDOStatement, Laravel\Config, Laravel\Event;
class Connection {
/**
* The raw PDO connection instance.
* 原始 PDO 连接实例。
* @var PDO
*/
public $pdo;
/**
* The connection configuration array.
* 连接配置数组。
* @var array
*/
public $config;
/**
* The query grammar instance for the connection.
* 连接的查询语法实例。
* @var Grammars\Grammar
*/
protected $grammar;
/**
* All of the queries that have been executed on all connections.
* 已在所有连接上执行的所有查询。
* @var array
*/
public static $queries = array();
/**
* Create a new database connection instance.
* 创建一个新的数据库连接实例。
* @param PDO $pdo
* @param array $config
* @return void
*/
public function __construct(PDO $pdo, $config)
{
$this->pdo = $pdo;
$this->config = $config;
}
/**
* Begin a fluent query against a table.
* 开始对表进行流畅的查询。
* <code>
* // Start a fluent query against the "users" table
* $query = DB::connection()->table('users');
*
* // Start a fluent query against the "users" table and get all the users
* $users = DB::connection()->table('users')->get();
* </code>
*
* @param string $table
* @return Query
*/
public function table($table)
{
return new Query($this, $this->grammar(), $table);
}
/**
* Create a new query grammar for the connection.
* 为连接创建新的查询语法。
* @return Query\Grammars\Grammar
*/
protected function grammar()
{
if (isset($this->grammar)) return $this->grammar;
switch (isset($this->config['grammar']) ? $this->config['grammar'] : $this->driver())
{
case 'mysql':
return $this->grammar = new Query\Grammars\MySQL($this);
case 'sqlsrv':
return $this->grammar = new Query\Grammars\SQLServer($this);
default:
return $this->grammar = new Query\Grammars\Grammar($this);
}
}
/**
* Execute a SQL query against the connection and return a single column result.
* 对连接执行 SQL 查询并返回单列结果。
* <code>
* // Get the total number of rows on a table
* $count = DB::connection()->only('select count(*) from users');
*
* // Get the sum of payment amounts from a table
* $sum = DB::connection()->only('select sum(amount) from payments')
* </code>
*
* @param string $sql
* @param array $bindings
* @return mixed
*/
public function only($sql, $bindings = array())
{
$results = (array) $this->first($sql, $bindings);
return reset($results);
}
/**
* Execute a SQL query against the connection and return the first result.
* 对连接执行 SQL 查询并返回第一个结果。
* <code>
* // Execute a query against the database connection
* $user = DB::connection()->first('select * from users');
*
* // Execute a query with bound parameters
* $user = DB::connection()->first('select * from users where id = ?', array($id));
* </code>
*
* @param string $sql
* @param array $bindings
* @return object
*/
public function first($sql, $bindings = array())
{
if (count($results = $this->query($sql, $bindings)) > 0)
{
return $results[0];
}
}
/**
* Execute a SQL query and return an array of StdClass objects.
* 执行 SQL 查询并返回 StdClass 对象数组。
* @param string $sql
* @param array $bindings
* @return array
*/
public function query($sql, $bindings = array())
{
list($statement, $result) = $this->execute($sql, $bindings);
// The result we return depends on the type of query executed against the
// database. On SELECT clauses, we will return the result set, for update
// and deletes we will return the affected row count. And for all other
// queries we'll just return the boolean result.
// 我们返回的结果取决于对数据库执行的查询类型。
// 在 SELECT 子句上，我们将返回结果集，对于更新和删除，我们将返回受影响的行数。
// 对于所有其他查询，我们将只返回布尔结果。
if (stripos($sql, 'select') === 0)
{
return $statement->fetchAll(PDO::FETCH_CLASS, 'stdClass');
}
elseif (stripos($sql, 'update') === 0 or stripos($sql, 'delete') === 0)
{
return $statement->rowCount();
}
else
{
return $result;
}
}
/**
* Execute a SQL query against the connection.
* 对连接执行 SQL 查询。
* The PDO statement and boolean result will be return in an array.
* PDO 语句和布尔结果将在数组中返回。
* @param string $sql
* @param array $bindings
* @return array
*/
protected function execute($sql, $bindings = array())
{
$bindings = (array) $bindings;
// Since expressions are injected into the query as strings, we need to
// remove them from the array of bindings. After we have removed them,
// we'll reset the array so there aren't gaps in the keys.
// 由于表达式是作为字符串注入到查询中的，我们需要将它们从绑定数组中删除。
// 删除它们后，我们将重置数组，以便键中没有间隙。
$bindings = array_values(array_filter($bindings, function($binding)
{
return ! $binding instanceof Expression;
}));
$sql = $this->grammar()->shortcut($sql, $bindings);
// Each database operation is wrapped in a try / catch so we can wrap
// any database exceptions in our custom exception class, which will
// set the message to include the SQL and query bindings.
// 每个数据库操作都包装在 try / catch 中，因此我们可以将任何数据库异常包装在我们的自定义异常类中，
// 这将设置消息以包含 SQL 和查询绑定。
try
{
$statement = $this->pdo->prepare($sql);
$start = microtime(true);
$result = $statement->execute($bindings);
}
// If an exception occurs, we'll pass it into our custom exception
// and set the message to include the SQL and query bindings so
// debugging is much easier on the developer.
// 如果发生异常，我们会将其传递到我们的自定义异常中，并将消息设置为包含 SQL 和查询绑定，以便开发人员更轻松地进行调试。
catch (\Exception $exception)
{
$exception = new Exception($sql, $bindings, $exception);
throw $exception;
}
// Once we have execute the query, we log the SQL, bindings, and
// execution time in a static array that is accessed by all of
// the connections actively being used by the application.
// 执行查询后，我们将 SQL、绑定和执行时间记录在一个静态数组中，该数组由应用程序正在使用的所有连接访问。
if (Config::get('database.profile'))
{
$this->log($sql, $bindings, $start);
}
return array($statement, $result);
}
/**
* Log the query and fire the core query event.
* 记录查询并触发核心查询事件。
* @param string $sql
* @param array $bindings
* @param int $start
* @return void
*/
protected function log($sql, $bindings, $start)
{
$time = number_format((microtime(true) - $start) * 1000, 2);
Event::fire('laravel.query', array($sql, $bindings, $time));
static::$queries[] = compact('sql', 'bindings', 'time');
}
/**
* Get the driver name for the database connection.
* 获取数据库连接的驱动程序名称。
* @return string
*/
public function driver()
{
return $this->pdo->getAttribute(PDO::ATTR_DRIVER_NAME);
}
/**
* Magic Method for dynamically beginning queries on database tables.
* 动态开始数据库表查询的魔术方法。
*/
public function __call($method, $parameters)
{
return $this->table($method);
}
}github地址： https://github.com/liu-shilong/laravel3-scr
标签：return,SQL,Laravel3.0,connection,源码,sql,query,array,bindings 来源： https://blog.csdn.net/qq2942713658/article/details/117636840