<?php





/**

* Database platform implementation for MySQL.

* @author Michal Palma <palmic at centrum dot cz>

* @copyleft (l) 2005-2006  Michal Palma

* @package DbControl

* @version 1.5

* @license http://opensource.org/licenses/gpl-license.php GNU Public License

* @date 2006-01-11

*/

class DbMysql extends DbPlatform

{



    //== Attributes ======================================================================

    //== constructors ====================================================================



    public function DbMysql(DbParametersMessenger $DbParametersMessenger, DbStateHandler $dbStateHandler) {

        if (!in_array("mysql", get_loaded_extensions())) {

            throw new DbControlException("Your PHP configuration does not support MySQL extension. Check php.ini.");

        }

        $this->dbParametersMessenger = $DbParametersMessenger;

        $this->dbStateHandler = $dbStateHandler;

    }



    //== destructors =====================================================================



    public function __destruct() {

        if ($this->activeTransaction) {

            if ($this->autoCommit) {

                $this->transactionCommit();

            }

            else {

                $this->transactionRollback();

            }

        }

        @mysql_close($this->connection);

    }





    //== public functions ================================================================



    public function fetchAssoc($result) {

        if (!is_resource($result)) {

            throw new DbControlException("Ilegal parameter result. Must be valid result resource.");

        }

        else {

            return @mysql_fetch_assoc($result);

        }

    }



    public function getLastId() {

        return @mysql_insert_id($this->getConnection());

    }



    public function selectDb(/*string*/ $dbName) {

        if (!is_string($dbName)) {

            throw new DbControlException("Ilegal parameter dbName. Must be string.");

        }

        try {

            $this->query("USE ". $dbName);

        }

        catch (Exception $e) {

            throw $e;

        }

    }



    public function query(/*string*/ $query) {

        if (!is_string($query)) {

            throw new DbControlException("Ilegal parameter query. Must be string.");

        }

        if (!$result = @mysql_query($query, $this->getConnection())) {

            $this->throwMysqlException();

        }

        return $result;

    }



    public function getNumRows(/*resource*/ $result) {

        if (!is_resource($result)) {

            throw new DbControlException("Ilegal parameter result. Must be valid result resource.");

        }

        else {

            return @mysql_num_rows($result);

        }

    }



    public function getColnames(/*resource*/ $result) {

        if (!is_resource($result)) {

            throw new DbControlException("Ilegal parameter result. Must be valid result resource.");

        }

        if (!$numFields = @mysql_num_fields($result)) {

            throw new DbControlException("No Column in result.");

        }

        for ($i = 0; $i < $numFields; $i++) {

            if (!$colname = @mysql_field_name($result, $i)) {

                $this->throwMysqlException("Colnames reading error.");

            }

            $colnames[$i] = $colname;

        }

        return $colnames;

    }



    public function getTableColumns(/*string*/ $schemaName, /*string*/ $tableName) {

        if (strlen($schemaName) < 1) {

            throw new DbControlException("Ilegal parameter schemaName. Must be string.");

        }

        if (strlen($tableName) < 1) {

            throw new DbControlException("Ilegal parameter tableName. Must be string.");

        }

        try {

            $dbSchema   = "information_schema";

            $sql        = "SELECT

                            COLUMN_NAME AS name,

                            DATA_TYPE AS type,

                            CHARACTER_OCTET_LENGTH AS length

                                FROM $dbSchema.COLUMNS

                                    WHERE TABLE_SCHEMA = '$schemaName'

                                    AND   TABLE_NAME   = '$tableName'";

            $result     = $this->query($sql);

            while ($row = $this->fetchAssoc($result)) {

                $length = (is_numeric($row["length"]) && $row["length"] > 0) ? "(". $row["length"] .")" : "";

                $columns[$row["name"]]["type"] = $row["type"] . $length;

            }

            return $columns;

        }

        catch (Exception $e) {

            throw $e;

        }

    }



    public function transactionStart(/*boolean*/ $autoCommit) {

        if (!is_bool($autoCommit)) {

            throw new DbControlException("Ilegal parameter autoCommit. Must be boolean.");

        }

        if (!$this->activeTransaction) {

            try {

                $this->query("BEGIN WORK");

            }

            catch (Exception $e) {

                throw $e;

            }

            $this->autoCommit = $autoCommit;

            $this->activeTransaction = true;

        }

        else {

            throw new DbControlException("Multiple transactions are not supported.");

        }

    }



    public function transactionCommit() {

        if ($this->activeTransaction) {

            try {

                $this->query("COMMIT");

            }

            catch (Exception $e) {

                throw $e;

            }

            $this->activeTransaction = false;

        }

        else {

            throw new DbControlException("No transaction active.");

        }

    }



    public function transactionRollback() {

        if ($this->activeTransaction) {

            try {

                $this->query("ROLLBACK");

            }

            catch (Exception $e) {

                throw $e;

            }

            $this->activeTransaction = false;

        }

        else {

            throw new DbControlException("No transaction active.");

        }

    }





    //== protected functions =============================================================



    protected function connect() {

        if(!is_resource($this->connection)) {



            // we are not using port value in MYSQL connection - there was problems with that.

//            if (strlen($this->dbParametersMessenger->port) > 0) {

//                $hostString = $this->dbParametersMessenger->loginHost .":". $this->dbParametersMessenger->port;

//            }

//            else {

//                $hostString = $this->dbParametersMessenger->loginHost;

//            }



            $this->connection = @mysql_pconnect($hostString, $this->dbParametersMessenger->loginName, $this->dbParametersMessenger->loginPassword);

            if (!is_resource($this->connection)) {

                # Exception code -1 for connection error

                throw new DbControlException("Cant connect to database mysql.\nhost = ". $this->dbParametersMessenger->loginHost, -1);

            }



            //setting prior charset for connection with MySQL just after connection is needeed from last versions (Espetialy for non-English signs)

            # Caution: Using $this->query() may rewrite query that is waiting for execute

            if (!@mysql_query("SET NAMES '". $this->dbStateHandler->getCharset() ."';", $this->connection)) {

                $this->throwMysqlException("Cannot set charset of DB session.");

            }

        }

    }



    /**

    * getter for connection

    * @return valid connection resource

    */

    protected function getConnection() {

        try {

            $this->connect();

        }

        catch (Exception $e) {

            throw $e;

        }

        return $this->connection;

    }



    /**

    * Throws Exception with Mysql error infos

    * @return void

    */

    protected function throwMysqlException(/*string*/ $addToMessage = "") {

        if (is_string($addToMessage)) {

            $message = $addToMessage ." \n". @mysql_error($this->connection);

        }

        else {

            $message = @mysql_error($this->connection);

        }

        throw new DbControlException($message, @mysql_errno($this->connection));

    }

}



?>