Going from mysql statements to PDO [closed] - php

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I need to rewrite all my code.. I was told last time I was in here, that I needed to choose between mysqli or PDO.. now I have choosen PDO - but I must say that I don't understand NOTHING at all..
For example I have this piece of code:
//get the email
$email = mysql_real_escape_string($_POST['email']);
//mysql query to select field email if it's equal to the email that we check '
$result = mysql_fetch_array(mysql_query("SELECT email FROM business_members WHERE email = '".$email."'"));
//if number of rows fields is bigger them 0 that means it's NOT available '
if($result['email'] == $email){
//and we send 0 to the ajax request
echo "0";
}else{
//else if it's not bigger then 0, then it's available '
//and we send 1 to the ajax request
echo "1";
}
Are there any sites that can help me understand a little better and I have tried to read on php-net, but it is very confusing..

Answer 1

The best thing about PDO is that its object orientated. So keeping to that form and making the most of it we can create a PDO CRUD class that handles all your database query's ect.
Here is an example, custom methods/functions can be added to enhance functionality ect:
<?php
Class PDO_CRUD{
private $db;
function __construct($host,$dbname,$user,$pass){
$this->dbhost = $host;
$this->dbname = $dbname;
$this->dbuser = $user;
$this->dbpass = $pass;
}
private function connect(){
if (!$this->db instanceof PDO){
$this->db = new PDO('mysql:dbname='.$this->dbname.';host='.$this->dbhost, $this->dbuser, $this->dbpass);
$this->db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
}
}
/*Raw Select*/
public function rawQuery($sql){
$this->connect();
return $this->db->query($sql)->fetchAll(PDO::FETCH_ASSOC);
}
public function get($table,$fieldname=null, $id=null){
$this->connect();
$sql = "SELECT * FROM $table WHERE $fieldname = :id";
$statement = $this->db->prepare($sql);
$statement->bindParam(':id', $id, PDO::PARAM_STR);
$statement->execute();
return $statement->fetchAll(PDO::FETCH_ASSOC);
}
/*Insert*/
public function put($table,$values){
$this->connect();
$fieldnames = array_keys($values[0]);
$sql = "INSERT INTO $table ";
$fields = '('.implode(' ,', $fieldnames).')';
$bound = '(:'.implode(', :', $fieldnames).')';
$sql .= $fields.' VALUES '.$bound;
$statement = $this->db->prepare($sql);
foreach($values as $vals){
$statement->execute($vals);
}
}
/*Update*/
public function update($table,$fieldname, $value, $pk, $id){
$this->connect();
$sql = "UPDATE $table SET $fieldname = :value WHERE $pk = :id";
$statement = $this->db->prepare($sql);
$statement->bindParam(':id', $id, PDO::PARAM_STR);
$statement->bindParam(':value', $value, PDO::PARAM_STR);
$statement->execute();
}
/*Update Hits*/
public function add_hit($table,$id){
$this->connect();
$sql = "UPDATE $table SET hits = hits + 1 WHERE url = :id";
$statement = $this->db->prepare($sql);
$statement->bindParam(':id', $id, PDO::PARAM_STR);
$statement->execute();
}
/*Delete*/
public function delete($table,$id){
$this->connect();
$sql = "DELETE FROM $table WHERE url = :id";
$statement = $this->db->prepare($sql);
$statement->bindParam(':id', $id, PDO::PARAM_STR);
$statement->execute();
}
}
//Then we have a nice way to access all our querys from one class.
//ini the model class
$model = new PDO_CRUD('localhost','yourDB','User','Password');
$insert = array(array('id'=>NULL,'somecol'=>'someval'));
$model->put('someTable',$insert);
//multiple inserts
$insert = array(array('id'=>NULL,'somecol'=>'someval123'),
array('id'=>NULL,'somecol'=>'someval1234'),
array('id'=>NULL,'somecol'=>'someval12345'));
$model->put('someTable',$insert);
//or delete a row
$model->delete('someTable',1);
//or a raw query
$model->rawQuery('DELETE FROM someTable');
?>

Answer 2

PHP File containing the PDO functions:
<?php
class example {
public function __construct() {
$this->db = new PDO('mysql:host=localhost;dbname=testdb;', 'user', 'password');
}
public function checkMail($email) {
// This is the prepared SQL statement
// The values which you want to filter for in your WHERE clause, are replaced by ?
$sql = "SELECT
email
FROM
business_members
WHERE
email = ?";
// Prepare the statement
$stmt = $this->db->prepare($sql);
// Bind a value to a question mark (the 1 means, the position of occurence of the question mark)
$stmt->bindParam(1, $email);
// Query the db, output debug info if query failed
if(!$stmt->execute()) {
// Only for debugging, don't use in production
var_dump($stmt->errorInfo());
}
// Load result to var
$result = $stmt->fetchAll(PDO::FETCH_ASSOC);
// Check amount of records
if(count($result) > 0) {
// Records found
return 1;
} else {
// No records found
return 0;
}
}
}
?>
Main file:
<?php
include 'includes/pdo.include.php';
$example = new example;
echo $example->checkMail($_POST['email']);
?>