Learning PDO in as possible correct way .

Database Connection using PDO and some basic functions

<?php
	class Database
	{
		private $conn;
		private $handle;
		
		public function __construct()
		{
		$dbhost = "localhost";
		$dbname = "pdo_test";
		$dbuser = "root";
		$dbpass = "";
		$charset = "utf8";
		
		/**
		* -database driver, host, db ( schema ) name and charset, as well as less frequently used port and unix_socket are going to DSN
		* -username and passwword are going to constructor
		* -al other options go to options array
		*/
		
		$dsn = "mysql:host=$dbhost;dbname=$dbname;charset=$charset"; // DSN is a semicolon-delimited string consist of param = vale pairs.( DSN = Data Source Name )
		
		$opt = array(
		    PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
			PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC
		);
		
		/**
		* Important Notes-
		*  -Unlike old mysql_ * functions, which can be used anywhere in the code, 
		    PDO is stored in a  regular variable, 
		    which means it can be inaccessible inside function - so, 
			one have to make it accessible , 
			by means of the global directive or it's more complicated analogue - an IoC container
		* -Connection have to be done only oncee !
    		No connects in every function ! 
			No connects in every  class constructor !
			Connection have to be done once and this variable have to be used all the way,
			Otherwise multiple connection will be created ,
			which will  eventually kill your database server
		*/
		try
		{
			$this->conn = new PDO( $dsn, $dbuser, $dbpass, $opt );
			//echo "Database connection successful.<br />";
		}
		catch(PDOException $e)
		{
			echo "Error in database connection !!!<br />";
			echo $e->getMessage();
		}
		}
		
		public function test($test)
		{
			echo "<br />".$test;
		}
		
		public function create($table, $data)
		{
			$query = "CREATE TABLE $table ($data);";
			
			$this->handle = $this->conn->prepare($query);
			if($this->handle->execute())
			{
				echo "$table created.<br />";
			}
		}
		
		public function insert($table, $data)
		{
			$keys = implode(',', array_keys($data));
			foreach($data as $key => $val)
			$data[$key] = "'".$val."'";
			$vals = implode(",",$data);
			$query = "INSERT INTO $table ($keys) VALUES ($vals);";
//			echo $query;
 			$this->handle = $this->conn->prepare($query);
			if($this->handle->execute())
			{
				 return $this->conn->lastInsertId(); 
			}
			else
			{	
				echo "Can not be added to database !!!";
			} 
		}
		

		public function select($table,$condition)
		{	
			$where = array();
			foreach($condition as $key => $value)
			{
				$where[] = "$key='$value'";
			}
			$var = implode(' AND ', $where);
			
			$query = "SELECT * FROM $table WHERE $var;"; 
		 	
			$this->handle = $this->conn->prepare($query);
			
			$indexes = $this->handle->execute();

			while($result = $this->handle->fetchAll(PDO::FETCH_ASSOC))
			{
				return($result);
			} 
		}
		
	 	function update($table, $data, $condition)
		{	
			$array=array();
			foreach($data as $key=>$val){
			$array[]=$key."='".$val."'";
			} 
			$values=implode(',',$array);
		
			$where = array();
			foreach($condition as $key => $value)
			{
				$where[] = "$key='$value'";
			}
			$var = implode(' AND ', $where);
			
			$query="UPDATE $table SET $values WHERE $var LIMIT 1;";
//			echo $query;
	 		
 			$this->handle=$this->conn->prepare($query);
			
			if($this->handle->execute())
			{
				return true;
			}
			else
			{
				return FALSE;
			}
		}
		
		
		
		public function delete($table,$condition)
		{
			$where = array();
			foreach($condition as $key => $value)
			{
				$where[] = "$key='$value'";
			}
			$var = implode(' AND ', $where);
			$query = "DELETE FROM $table WHERE $var LIMIT 1;";
//			echo $query;
			
			$this->handle = $this->conn->prepare($query);
			if($this->handle->execute())
			{
				return true;
			}
			else
			{
				echo "Delete operation is not performed due to some problem !!<br />";
			}
			
		}
		
		public function login( $table, $email, $password )
		{
			$query = "SELECT id, first_name, last_name, email, password FROM $table WHERE email = :email AND password = :password";
			$this->handle = $this->conn->prepare( $query, array( PDO::ATTR_CURSOR => PDO::CURSOR_FWDONLY ) );
			$this->handle->execute(array(':email' => $email, ':password' => $password ) );
			
			$count = $this->handle->rowCount();
			if( $count == 1 ) {
			$result = $this->handle->fetch( PDO::FETCH_ASSOC ); 
			/**
			* Try using PDO::FETCH_LAZY allows all three (numeric associative and object) methods 
			  without memory overhead
			* PDO::FETCH_OBJ returns object
			* PDOStatement::fetchAll() use this when data need to be passed to template and not to be outputed directly
			*/
			return $result;
			}
		}
		
		public function __destruct()
		{
			$this->conn = null;
			if(!$this->conn)
			{
		//	echo "<br />database disconnected !!";
			}
		}
	}
	

?>