A class written to simplify the use oh mysqli in php. Uses similar concepts to other db classes built into other frameworks. Download the file here or look at the code below.

<?php
	class Database{ 
		public $host     = DB_HOST;
		public $database = DB_DATABASE;
		public $username = DB_USER;
		public $password = DB_PASSWORD;
		public $link    = 0;
		public $result  = 0;
		public $record   = array();
		public $row;
		public $errNo    = 0;
		public $error    = "";
	    
		/* Call connection method upon constructing
		 * Pass in true if you want a second connection object
		 * Example:
		 * 		$db2 = new Database(true);
		 * 		$db2->database = $config['MC_DB_Username'];
		 * 		$db2->username = $config['MC_DB_Username'];
		 * 		$db2->password = $config['MC_DB_Password'];
		 * 		$db2->host = $config['MC_DB_Host'];
		 * 		$db2->createConnection();
		 * */
		public function __construct($noconnect = false){
			if(!$noconnect){
				$this->createConnection(); 
			}
		}

		/* Connection to the database */
		public function createConnection(){ 
	        if( 0 == $this->link ) 
	            $this->link=mysqli_connect( $this->host, $this->username, $this->password );
			if( !$this->link ) 
	   			$this->stopExec( "Trying to connect.... Result: failed" );
			if( !mysqli_select_db($this->link,$this->database)) 
	            $this->stopExec( "Cannot use database ".$this->database );
		} 
	
		/* Execute query string */
	 	public function query($queryString,$echo = false,$exit = true){
	 		if($echo == true){ echo "<br>".htmlspecialchars($queryString)."<br>"; } 
			$this->result = mysqli_query($this->link, $queryString);
			$this->row = 0; 
			$this->errNo = mysqli_errno($this->link);
			$this->error = mysqli_error($this->link);
			if(!$this->result){
				$this->stopExec( "Invalid SQL String: ".$queryString , $exit );
			}else{
				if(IS_DEV){
					global $clean;
					$newlink = mysqli_connect( $this->host, $this->username, $this->password );
					mysqli_select_db($newlink,$this->database);
					mysqli_query($newlink, "INSERT INTO `ServerLog`(`Message`)VALUES('".$clean->UserInput($queryString)."')");
				}
			}
			return $this->result; /* return the resource id of query. You can either then call fetchRecord method. */
	    } 
	 
		public function fetchRecord($type = 1, $result = null){
			/* Get from specific result */
			if($result != null){
				$this->result = $result;
			}
			
			if(is_bool($this->result)){
				return "boolean given, check query";
			}
			 
			/* 1 --> for array 2 --> for object */
			if($type == 1){
				$record = mysqli_fetch_array($this->result); /*return array */
			}else{
				$record = mysqli_fetch_object($this->result); /*return object */
			}
	  
			return $record;
		}
		
		/* Stop the execution of query when there's an error */
		public function stopExec($msg,$exit){ 
			serverlog("[MySQL Error][".$this->errNo."] ".$this->error." Message: ".$msg,'crucial');
			if($exit){
				header('Location: http://'.SYS_URL_PATH.'/error.php?code=10');
			}
			
			exit();
		} 
	 
		/* Get the number of row */
		public function numRows($result = null){
			if($result != null){
				return mysqli_num_rows($result);
			}else{
				return mysqli_num_rows($this->result);
			}
			
		}
		
		/* Get the the last insert id */
		public function lastID(){
			return mysqli_insert_id($this->link);
		}
		
		public function real_escape_string($str){
			return mysqli_real_escape_string($this->link,$str);
		}
	}