Subversion-Projekte lars-tiefland.prado

<?php
/**
 * TDbMetaData class file.
 *
 * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
 * @link http://www.pradosoft.com/
 * @copyright Copyright &copy; 2005-2008 PradoSoft
 * @license http://www.pradosoft.com/license/
 * @version $Id: TDbMetaData.php 2541 2008-10-21 15:05:13Z qiang.xue $
 * @package System.Data.Common
 */

/**
 * TDbMetaData is the base class for retrieving metadata information, such as
 * table and columns information, from a database connection.
 *
 * Use the {@link getTableInfo} method to retrieve a table information.
 *
 * @author Wei Zhuo <weizho[at]gmail[dot]com>
 * @version $Id: TDbMetaData.php 2541 2008-10-21 15:05:13Z qiang.xue $
 * @package System.Data.Common
 * @since 3.1
 */
abstract class TDbMetaData extends TComponent
{
        private $_tableInfoCache=array();
        private $_connection;

        /**
         * @param TDbConnection database connection.
         */
        public function __construct($conn)
        {
                $this->_connection=$conn;
        }

        /**
         * @return TDbConnection database connection.
         */
        public function getDbConnection()
        {
                return $this->_connection;
        }

        /**
         * Obtain database specific TDbMetaData class using the driver name of the database connection.
         * @param TDbConnection database connection.
         * @return TDbMetaData database specific TDbMetaData.
         */
        public static function getInstance($conn)
        {
                $conn->setActive(true); //must be connected before retrieving driver name
                $driver = $conn->getDriverName();
                switch(strtolower($driver))
                {
                        case 'pgsql':
                                Prado::using('System.Data.Common.Pgsql.TPgsqlMetaData');
                                return new TPgsqlMetaData($conn);
                        case 'mysqli':
                        case 'mysql':
                                Prado::using('System.Data.Common.Mysql.TMysqlMetaData');
                                return new TMysqlMetaData($conn);
                        case 'sqlite': //sqlite 3
                        case 'sqlite2': //sqlite 2
                                Prado::using('System.Data.Common.Sqlite.TSqliteMetaData');
                                return new TSqliteMetaData($conn);
                        case 'mssql': // Mssql driver on windows hosts
                        case 'dblib': // dblib drivers on linux (and maybe others os) hosts
                                Prado::using('System.Data.Common.Mssql.TMssqlMetaData');
                                return new TMssqlMetaData($conn);
                        case 'oci':
                                Prado::using('System.Data.Common.Oracle.TOracleMetaData');
                                return new TOracleMetaData($conn);
//                      case 'ibm':
//                              Prado::using('System.Data.Common.IbmDb2.TIbmDb2MetaData');
//                              return new TIbmDb2MetaData($conn);
                        default:
                                throw new TDbException('ar_invalid_database_driver',$driver);
                }
        }

        /**
         * Obtains table meta data information for the current connection and given table name.
         * @param string table or view name
         * @return TDbTableInfo table information.
         */
        public function getTableInfo($tableName=null)
        {
                $key = $tableName===null?$this->getDbConnection()->getConnectionString():$tableName;
                if(!isset($this->_tableInfoCache[$key]))
                {
                        $class = $this->getTableInfoClass();
                        $tableInfo = $tableName===null ? new $class : $this->createTableInfo($tableName);
                        $this->_tableInfoCache[$key] = $tableInfo;
                }
                return $this->_tableInfoCache[$key];
        }

        /**
         * Creates a command builder for a given table name.
         * @param string table name.
         * @return TDbCommandBuilder command builder instance for the given table.
         */
        public function createCommandBuilder($tableName=null)
        {
                return $this->getTableInfo($tableName)->createCommandBuilder($this->getDbConnection());
        }

        /**
         * This method should be implemented by decendent classes.
         * @return TDbTableInfo driver dependent create builder.
         */
        abstract protected function createTableInfo($tableName);

        /**
         * @return string TDbTableInfo class name.
         */
        protected function getTableInfoClass()
        {
                return 'TDbTableInfo';
        }
}