时间:2021-07-01 10:21:17 帮助过:27人阅读
1、CI_DB_mysql_driver 继承CI_DB, CI_DB这个类是不存在的,每次调用文件中~/CodeIgniter_2.1.3/system/database/DB.php函数DB来初始化database的时候, 根据用户是否开启active_record,生成继承CI_DB_active_record或CI_DB_driver类的CI_DB类, 2、CI_DB_a
1、CI_DB_mysql_driver 继承 CI_DB, CI_DB这个类是不存在的,每次调用文件中~/CodeIgniter_2.1.3/system/database/DB.php函数&DB来初始化database的时候,
根据用户是否开启active_record,生成继承CI_DB_active_record或CI_DB_driver类的CI_DB类,
2、CI_DB_active_record类继承CI_DB_driver类
require_once(BASEPATH.'database/DB_driver.php'); if ( ! isset($active_record) OR $active_record == TRUE) { require_once(BASEPATH.'database/DB_active_rec.php'); if ( ! class_exists('CI_DB')) { eval('class CI_DB extends CI_DB_active_record { }'); } } else { if ( ! class_exists('CI_DB')) { eval('class CI_DB extends CI_DB_driver { }'); } }
3、最终会调用顶级父类CI_DB_driver的构造方法,将数据库配置的各字段赋值到CI_DB_driver类的各个字段上,
$active_group = 'default'; $active_record = TRUE; $db['default']['hostname'] = 'localhost'; $db['default']['username'] = ''; $db['default']['password'] = ''; $db['default']['database'] = ''; $db['default']['dbdriver'] = 'mysql'; $db['default']['dbprefix'] = ''; $db['default']['pconnect'] = TRUE; $db['default']['db_debug'] = TRUE; $db['default']['cache_on'] = FALSE; $db['default']['cachedir'] = ''; $db['default']['char_set'] = 'utf8'; $db['default']['dbcollat'] = 'utf8_general_ci'; $db['default']['swap_pre'] = ''; $db['default']['autoinit'] = TRUE; var $username; var $password; var $hostname; var $database; var $dbdriver = 'mysql'; var $dbprefix = ''; var $char_set = 'utf8'; var $dbcollat = 'utf8_general_ci'; var $autoinit = TRUE; var $port = ''; var $pconnect = FALSE; var $db_debug = FALSE;
如果autoinit自动初始化为TRUE,则将DB初始化,这个DB对象是CI_DB_mysql_driver类
require_once(BASEPATH.'database/DB_driver.php'); if ( ! isset($active_record) OR $active_record == TRUE) { require_once(BASEPATH.'database/DB_active_rec.php'); if ( ! class_exists('CI_DB')) { eval('class CI_DB extends CI_DB_active_record { }'); } } else { if ( ! class_exists('CI_DB')) { eval('class CI_DB extends CI_DB_driver { }'); } } require_once(BASEPATH.'database/drivers/'.$params['dbdriver'].'/'.$params['dbdriver'].'_driver.php'); // Instantiate the DB adapter $driver = 'CI_DB_'.$params['dbdriver'].'_driver'; $DB = new $driver($params); if ($DB->autoinit == TRUE) { $DB->initialize(); } return $DB;