<?php





/**

* Database platform implementation for ODBC.

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



* @package DbControl

* @version 1.5



* @date 2006-01-11

*/

class DbOdbc extends DbPlatform

{



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

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



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

        $this->dbParametersMessenger = $DbParametersMessenger;

        $this->dbStateHandler = $dbStateHandler;

    }



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



    public function __destruct() {

        if ($this->activeTransaction) {

            if ($this->autoCommit) {

                $this->transactionCommit();

            }

            else {

                $this->transactionRollback();

            }

        }

        @odbc_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 {

            # odbc_fetch_array returns the same array like forexample mysql_fetch_assoc (array associated by colnames)

            return $row = odbc_fetch_array($result);

        }

    }



    public function getLastId() {

        try {

            $result = $this->query("SELECT LAST_INSERT_ID()");

            $id = @odbc_result($result, 1);

        }

        catch (Exception $e) {

            throw new DbControlException("Error in trying to acquire Last inserted id.\n" . $e->getMessage(), $e->getCode());

        }

        return $id;

    }



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

            $this->throwOdbcException();

        }

        return $result;

    }



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

        if (!is_resource($result)) {

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

        }

        else {

            return @odbc_num_rows($result);

        }

    }



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

        if (!is_resource($result)) {

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

        }

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

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

        }

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

            if (!$colname = @odbc_field_name($result, $i + 1)) {

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

            }

            $colnames[$i] = $colname;

        }

        return $colnames;

    }



    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)) {

            $cursorType = "SQL_CUR_USE_ODBC";

            $this->connection = @odbc_pconnect($this->dbParametersMessenger->dsn, $this->dbParametersMessenger->loginName, $this->dbParametersMessenger->loginPassword, $cursorType);

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

                # Exception code -1 for connection error

                throw new DbControlException("Cant connect to database ODBC.\nhost = ". $this->dbParametersMessenger->loginHost ."\nDSN = ". $this->dbParametersMessenger->dsn ."\ncursor type = ". $cursorType, -1);

            }

            //setting prior charset for connection with ODBC 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 (!@odbc_exec($this->connection, "SET NAMES '". $this->dbStateHandler->getCharset() ."';")) {

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

            }


            //setting default task database schema - if defined 
            # Caution: Using $this->query() may rewrite query that is waiting for execute
            if (strlen($schema = $this->dbParametersMessenger->schema) > 0) {            	
	            if (!@odbc_exec($this->connection, "USE $schema;")) {
	                $this->throwOdbcException("Cannot select default database schema '$schema'.");
	            }
            }
        }

    }



    /**

    * getter for connection

    * @return valid connection resource

    */

    protected function getConnection() {

        try {

            $this->connect();

        }

        catch (Exception $e) {

            throw $e;

        }

        return $this->connection;

    }



    /**

    * Throws Exception with ODBC error infos

    * @return void

    */

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

        if (is_string($addToMessage)) {

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

        }

        else {

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

        }

        # ODBC error code can be invalid for Exception code..

        $message = "Message: ". $message ."\nCode: ". @odbc_error($this->connection);

        throw new DbControlException($message);

    }

}



?>