<?
/**
* database layer for mysql
*/



class db
{
	/**
	* @var string database
	* @access private
	*/
	var $database = "";


	/**
	* @var string server
	* @access private
	*/
	var $server   = "";


	/**
	* @var string user
	* @access private
	*/
	var $user     = "";


	/**
	* @var string password
	* @access private
	*/
	var $password = "";


	/**
	* @var string tableprefix
	* @access private
	*/
	var $tableprefix = "webpm_";


	/**
	* @var resource link_id stores the mysql link identifier
	* @access private
	*/
	var $link_id  = 0;



	/**
	* @var integer querycounter
	* @access private
	*/
	var $querycounter = 0;


	/**
	* @var array queries
	* @access private
	*/
	var $queries=array();



	/**
	* constructor
	*
	* @param string server
	* @param string user
	* @param string password
	* @param string database
	* @param string tableprefix
	*/
	function db($server,$user,$password,$database,$tableprefix)
	{
		$this->server=$server;
		$this->user=$user;
		$this->password=$password;
		$this->database=$database;
		$this->tableprefix=$tableprefix;
		$this->querycounter=0;
		$this->queries=array();
		$this->querytimer=array();

		$this->link_id=0;
		$this->connect();
	}





	/**
	* open a connection to the database server
	*
	* @return void
	* @access private
	*/
	function connect()
	{
		if($this->link_id==0)
		{
			$this->link_id=mysql_connect($this->server,$this->user,$this->password);
			if(!$this->link_id)
			{
				$this->error("cannot connect to database server ".$this->server);
			}
			if($this->database!="")
			{
				$this->select_db();
			}
		}
	}





	/**
	* selects a database
	*
	* @param string databse
	* @return void
	* @access public
	*/
	function select_db($database="")
	{
		if($database!="")
		{
			$this->database=$database;
		}
		if(!@mysql_select_db($this->database, $this->link_id))
		{
			$this->error("cannot use database ".$this->database);
		}
	}






	/**
	* sends and execute a sql query
	*
	* @param string query_string
	* @return resource result
	* @access public
	*/
	function query($query_string)
	{
		$result = mysql_query($query_string,$this->link_id);
		$this->queries[]=$query_string;
		if(!$result)
		{
			$this->error("Invalid SQL: ".$query_string);
		}
		$this->querycounter++;
		return $result;
	}



	/**
	* fetches a result row as an associative array, a numeric array, or both
	*
	* @param resource result
	* @param integer result_type
	* @return array result row
	* @access public
	*/
	function fetch_array($result,$result_type=MYSQL_BOTH)
	{
		return @mysql_fetch_array($result,$result_type);
	}




	/**
	* free result memory
	*
	* @param resource result
	* @return boolean
	* @access public
	*/
	function free_result($result)
	{
		return @mysql_free_result($result);
	}




	/**
	* sends a sql query and fetches the first result row as an associative array, a numeric array, or both
	*
	* @param string query_string
	* @param integer result_type
	* @return array result row
	* @access public
	*/
	function query_first($query_string,$result_type=MYSQL_BOTH)
	{
		$result = $this->query($query_string);
		$returnarray=$this->fetch_array($result,$result_type);
		$this->free_result($result);
		return $returnarray;
	}




	/**
	* sends an SQL query to MySQL, without fetching and buffering the result rows
	*
	* @param string query_string
	* @param integer low_priority
	* @return resource result
	* @access public
	*/
	function unbuffered_query($query_string,$low_priority=0)
	{
		global $phpversion;

		if($phpversion<406)
		{
			return $this->query($query_string);
		}
		else
		{
			if($low_priority==1)
			{
				$query_string=preg_replace("/^(REPLACE|INSERT|UPDATE|DELETE)/im","\\1 LOW_PRIORITY", $query_string);
			}
			$result = mysql_unbuffered_query($query_string,$this->link_id);
			$this->queries[]="unbuffered: $query_string";
			if(!$result) $this->error("Invalid SQL: ".$query_string);
			$this->querycounter++;
			return $result;
		}
	}




	/**
	* returns the number of rows in result
	*
	* @param resource result
	* @return integer number_of_rows
	* @access public
	*/
	function num_rows($result)
	{
		return @mysql_num_rows($result);
	}




	/**
	* returns the number of affected rows in previous MySQL operation
	*
	* @return integer affected_rows
	* @access public
	*/
	function affected_rows()
	{
		return mysql_affected_rows($this->link_id);
	}




	/**
	* returns the primary key generated from the previous INSERT operation
	*
	* @return integer id
	* @access public
	*/
	function insert_id()
	{
		return mysql_insert_id($this->link_id);
	}



	/**
	* dies with an error message
	*
	* @param string msg error message
	* @return void;
	* @access private
	*/
	function error($msg)
	{
		die("<font face=Verdana size=2><b>Database error</b><br>
		$msg<br><br>
		mysql error: ".mysql_error()."<br>
		mysql error no: ".mysql_errno());
	}




	/**
	* returns the tableprefix
	*
	* @return string tableprefix
	* @access public
	*/
  	function getPrefix()
	{
		return $this->tableprefix;
   	}




	/**
	* print outs the number of sql queries and the executed sql queries.
	*
	* @return void
	* @access public
	*/
	function debug()
   	{
		echo "<p align='center' class='small'>SQL Queries: ".$this->querycounter."</p>\n";
		echo "<ul class='small'>\n";
		for($i=0;$i<$this->querycounter;$i++) echo "<li>".$this->queries[$i]."</li>\n";
		echo "</ul>\n";
   	}
}
?>