PHP - Database Interface Class

<?php
/**
 * File: Database.php
 *
 * This class is designed to be the interface class with a database.
 * This is currently setup to use SQL syntax however can be changed if needed in future for a different type of database.
 * Using this class will save a lot of programming if a change was needed.
 * Also works brilliantly for MySQL, used in 3 major projects so far :)
 *
 *
 * @author     Daniel Rosser
 * @version    1.0
 *
 */


class Database {
    private $HOST  = "example.com";
    private $TABLE = "table";
    private $USER  = "";
    private $PASS  = "";
    private $ERROR_CONNECT = "Could not connect to Database";
    private $ERROR_QUERY   = "Could not query the Database";
    private $connection;
    private $lastResult;

    /**
     * Constructor
     * @param type - Type of connection, Read only, Write
     */
    function __construct($type)  //php 5+ style constructor
    {
      switch ($type) {
      case readWrite:
          $this->USER = "username";
          $this->PASS = "password";
          break;
      case readWriteCreate:
          $this->USER = "username";
          $this->PASS = "password";
          break;
      case readOnly:
      default:
          $this->USER = "username";
          $this->PASS = "password";
          break;
       }
       $this->connect();
    }

    /**
     * Destructor
     */
    function __destruct()
    {
       $this->close;
       }

    /**
     * Connect to the database
     * @return connection
     */

    function connect()
    {
       $this->connection = mysql_connect($this->HOST,$this->USER,$this->PASS) or print mysql_error($this->ERROR_CONNECT);
       $result = mysql_select_db($this->TABLE,$this->connection);
       return($connection);
    }

    /**
     * Delete a row from a table
     * @param table - Table name
     * @param id - ID of row
     * @return result
     */
    function delete($table, $id)
    {
       $query = "DELETE FROM $table WHERE id='$id'";
       $result = mysql_query($query,$this->connection) or print mysql_error($this->ERROR_QUERY);
       return($result);
    }

    /**
     * Delete a row from a table
     * @param table - Table name
     * @param idName - name of the ID row
     * @param id - ID of row
     * @return result
     */
    function deleteSpecific($table, $idName, $id)
    {
       $query = "DELETE FROM $table WHERE $idName='$id'";
       $result = mysql_query($query,$this->connection) or print mysql_error($this->ERROR_QUERY);
       return($result);
    }

    /**
     * Disconnects and closes the connection with database
     */
    function disconnect()
    {
       mysql_close($this->connection);
    }

    /**
     * Insert fields, values into Table
     * @param table - Table name
     * @param fields - Fields to insert
     * @param values - Values to insert
     */
    function insert( $table, $fields, $values )
    {
      $start  = "INSERT INTO $table(";
      $middle = ") VALUES (";
      $end    = ")";
      $size   = sizeof($fields); // verify the size of the fields
      $stringFields = "";
      for($i=0;$i <= ($size-1);$i++){
        $stringFields .= "$fields[$i]";
        if( $i != ($size-1) ){
        $stringFields .= ",";
        }
      }
      $stringValues="";
      for( $k=0; $k <= ($size-1); $k++ ){
          $stringValues .= "\"$values[$k]\"";
          if( $k != ($size-1) ){
            $stringValues .= ",";
          }
       }
      $insert = "$start$stringFields$middle$stringValues$end";
      $insert = str_replace('""', mysql_escape_string("NULL"), $insert);
      $insert = str_replace('" "', mysql_escape_string("NULL"), $insert);
      $insert= str_replace("''", "", $insert);
      $insert = str_replace("' '", "", $insert);
      $this->query($insert);
    }

    /**
     * Update fields, values into Table
     * @param table - Table name
     * @param fields - Fields to insert
     * @param values - Values to insert
     * @param idName - Name of Primary Key row
     * @param id - The unique identifier
     */
    function update( $table, $fields, $values, $idName, $id )
    {
      $start  = "UPDATE $table SET ";
      $end    = " WHERE $idName=\"$id\";";
      $size   = sizeof($fields); // verify the size of the fields
      $sizeV  = sizeof($values);
      if($sizeV != $size)
        echo "Developer Error, Size of Fields / Values are not the same- Fields:$size Values:$sizeV";

      $string = "";
      for($i=0;$i <= ($size-1);$i++){
        $string .= "$fields[$i] = \"$values[$i]\"";
        if( $i != ($size-1) ){
        $string .= " , ";
        }
      }
      $update = "$start$string$end";
      $update = str_replace('""', mysql_escape_string("NULL"), $update);
      $update = str_replace('" "', mysql_escape_string("NULL"), $update);
      $update = str_replace("''", "", $update);
      $update = str_replace("' '", "", $update);
      $this->query($update);
    }

    /**
     * Use this for a SQL Query
     * Data is stored inside $this->lastResult
     * @param sql - SQL to query the database
     */
    function query($sql)
    {
      if(!($this->lastResult = mysql_query($sql, $this->connection)))
        die("MySQL Error from Query. Error: ".mysql_error()." From SQL : $sql");
    }

    /**
     * Fetch rows from last query
     * @return row array
     */
    function fetchRow()
    {
        return mysql_fetch_array($this->lastResult);
    }

    /**
     * Fetch rows from last query
     * @return an associative array that corresponds to the fetched row and moves the internal data pointer ahead
     */
    function fetchRowAssociative()
    {
        return mysql_fetch_assoc($this->lastResult);
    }



    /**
     * Number of rows in a table
     * @param table - Table to query
     */
    function number($table)
    {
        $query  = "SELECT * FROM $table";
        $result = mysql_query($query, $this->connection);
        $number = mysql_num_rows($result);
        return($number);
    }

    /**
     * Return the last id of an insertion
     * @return last id of an insertion
     */
    function lastId()
    {
       return mysql_insert_id($this->connection);
    }

    /**
     * Return the number of rows affected on last query
     * @return number of rows
     */
    function numberAffected()
    {
       $query = mysql_affected_rows();
       return($query);
    }

    /**
     * Return the number of rows in the last query
     * @return number of rows
     */
    function numberOfRows()
    {    $number = mysql_num_rows($this->lastResult);
        return($number);
    }

    /**
     * Return the number of rows found in a query
     * @return number of rows
     */
    function numberRows($query)
    {
      $result = mysql_query($query, $this->connection);
      $number = mysql_num_rows($result);
      return($number);
    }

};

?>