将Php连接到mssql server 2014时出错

Question

我正在尝试通过php连接mssql server 2014。我正在执行的脚本在我的网络托管上是实时的，这是我正在运行的脚本

<?php 
    $data_source='remoteds';
    $user='<username>';
    $password='<password>';

    // Connect to the data source and get a handle for that connection.
    $conn=odbc_connect($data_source,$user,$password);
    if (!$conn){
        if (phpversion() < '4.0'){
        exit("Connection Failed: . $php_errormsg" );
        }
        else{
        exit("Connection Failed:" . odbc_errormsg() );
        }
    }else
    {
    echo "Done!";
    }

    // Retrieves table list.
    $result = odbc_tables($conn);

    $tables = array();
    while (odbc_fetch_row($result))
        array_push($tables, odbc_result($result, "TABLE_NAME") );
    // Begin table of names.
        echo "<center> <table border = 1>";
        echo "<tr><th>Table Count</th><th>Table Name</th></tr>";
    // Create table rows with data.
    foreach( $tables as $tablename ) {
        $tablecount = $tablecount+1;
        echo "<tr><td>$tablecount</td><td>$tablename</td></tr>";
    }

    // End table.
    echo "</table></center>";
    // Disconnect the database from the database handle.
    odbc_close($conn);
    print e.g. 'Current PHP version: 4.1.1'

 ?>

我得到的错误是

在第18行的sql.php中调用未定义的函数odbc_connect（）