[李景山php]每天laravel-20161120|MySqlConnector.php

<?php

namespace Illuminate\Database\Connectors;

use PDO;
// this is mysql connection class
class MySqlConnector extends Connector implements ConnectorInterface
{// extends adn implements make class become more powerful
    // this is mysql connection
    /**
     * Establish a database connection.
     *
     * @param  array  $config
     * @return \PDO
     */
    public function connect(array $config)
    {// Establish a database connection
        $dsn = $this->getDsn($config);// first to get the dsn string

        $options = $this->getOptions($config);// second ,get the options

        // We need to grab the PDO options that should be used while making the brand
        // new connection instance. The PDO options control various aspects of the
        // connection's behavior, and some might be specified by the developers.
        $connection = $this->createConnection($dsn, $config, $options);
// we need to grab the pdo options that should be bused while making the brand new connection instance.
// The PDO options control various aspects of connections's behavior,and some might be specified by the developers.
        if (isset($config['unix_socket'])) {
            $connection->exec("use `{$config['database']}`;");
        }// set the unix_socket

        $collation = $config['collation'];//set the collation

        // Next we will set the "names" and "collation" on the clients connections so
        // a correct character set will be used by this client. The collation also
        // is set on the server but needs to be set here on this client objects.
        $charset = $config['charset'];
        // Next we will set the "names" and "collation" on the clients connections so a correct char

        $names = "set names '$charset'".
            (! is_null($collation) ? " collate '$collation'" : '');

        $connection->prepare($names)->execute();

        // Next, we will check to see if a timezone has been specified in this config
        // and if it has we will issue a statement to modify the timezone with the
        // database. Setting this DB timezone is an optional configuration item.
        if (isset($config['timezone'])) {
            $connection->prepare(
                'set time_zone="'.$config['timezone'].'"'
            )->execute();
        }// database name charset and timezone

        $this->setModes($connection, $config);// set the mode

        return $connection;
    }// just return the connection

    /**
     * Create a DSN string from a configuration.
     *
     * Chooses socket or host/port based on the 'unix_socket' config value.
     *
     * @param  array   $config
     * @return string
     */
    protected function getDsn(array $config)
    {
        return $this->configHasSocket($config) ? $this->getSocketDsn($config) : $this->getHostDsn($config);
    }// create a dsn string from a configuration

    /**
     * Determine if the given configuration array has a UNIX socket value.
     *
     * @param  array  $config
     * @return bool
     */
    protected function configHasSocket(array $config)
    {
        return isset($config['unix_socket']) && ! empty($config['unix_socket']);
    }

    /**
     * Get the DSN string for a socket configuration.
     *
     * @param  array  $config
     * @return string
     */
    protected function getSocketDsn(array $config)
    {
        return "mysql:unix_socket={$config['unix_socket']};dbname={$config['database']}";
    }

    /**
     * Get the DSN string for a host / port configuration.
     *
     * @param  array  $config
     * @return string
     */
    protected function getHostDsn(array $config)
    {
        extract($config, EXTR_SKIP);

        return isset($port)
                        ? "mysql:host={$host};port={$port};dbname={$database}"
                        : "mysql:host={$host};dbname={$database}";
    }

    /**
     * Set the modes for the connection.
     *
     * @param  \PDO  $connection
     * @param  array  $config
     * @return void
     */
    protected function setModes(PDO $connection, array $config)
    {// set te session sql_mode in this hash mode
        if (isset($config['modes'])) {
            $modes = implode(',', $config['modes']);

            $connection->prepare("set session sql_mode='".$modes."'")->execute();
        } elseif (isset($config['strict'])) {
            if ($config['strict']) {
                $connection->prepare("set session sql_mode='ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION'")->execute();
            } else {
                $connection->prepare("set session sql_mode='NO_ENGINE_SUBSTITUTION'")->execute();
            }
        }
    }
}