How to write mysql query into PDO

Question

Appreciate if you could help me to write below mysql code to PDO statement.

     $sql  = "SELECT * FROM node WHERE node_name='$nodename'";

     $result = mysql_query($sql);

when I read on PDO::query Manual i found this code

      <?php
      $connection = new pdo("sqlite:file.sq3");
      $query="SELECT * FROM table";
      $result = $connection->query($query);
      $row = $result->fetch(PDO::FETCH_ASSOC);
      print_r($row);
      ?>

what is the function for "sqlite:file.sq3" and "(PDO::FETCH_ASSOC)"

Answer 1

That line points to your sql file, there is no function for it. It opens a PDO connection and you can query further.

$connection = new pdo("sqlite:/path/to/sql/file.sq3");

PDO::FETCH_ASSOC tells the function fetch() to pull associative array from table.

Answer 2

you connect to the database like this :

try {
$db = new PDO("sqlite:file.sq3");
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    } catch (PDOException $e) {
       echo 'Error : <br>' . $e->getMessage();
}

PS: You dont need the try and the catch, but we used to get the error and handle it in a nice way as we want to

and next we query like this :

 $db->query(SELECT * FROM node WHERE node_name='$nodename'");

and we fetch it like this :

 $query = $db->query(SELECT * FROM node WHERE node_name='$nodename'");
 $row   = $query->fetch(PDO::FETCH_OBJ);

and now you use $row->name for example

here is more about PDO::FETCH

• PDO::FETCH_ASSOC : returns an array indexed by column name as returned in your result set

• PDO::FETCH_BOTH (default): returns an array indexed by both column name and 0-indexed column number as returned in your result set

• PDO::FETCH_BOUND : returns TRUE and assigns the values of the columns in your result set to the PHP variables to which they were
  bound with the PDOStatement::bindColumn() method

• PDO::FETCH_CLASS : returns a new instance of the requested class, mapping the columns of the result set to named properties in the
  class. If fetch_style includes PDO::FETCH_CLASSTYPE (eg
  PDO::FETCH_CLASS | PDO::FETCH_CLASSTYPE) then the name of the class
  is determined from a value of the first column.

• PDO::FETCH_INTO : updates an existing instance of the requested class, mapping the columns of the result set to named properties in
  the class

• PDO::FETCH_LAZY : combines PDO::FETCH_BOTH and PDO::FETCH_OBJ, creating the object variable names as they are accessed

• PDO::FETCH_NUM : returns an array indexed by column number as returned in your result set, starting at column 0

• PDO::FETCH_OBJ : returns an anonymous object with property names that correspond to the column names returned in your result set

Answer 3

If you were using MySQL before, I don't think the sqlite DSN is correct for you. SQLite is a different brand of RDBMS, and it's not compatible with MySQL.

To use PDO to connect to MySQL, see this manual page: http://www.php.net/manual/en/ref.pdo-mysql.connection.php

Example:

<?php
$dsn = 'mysql:host=localhost;dbname=testdb';
$username = 'username';
$password = 'password';

$dbh = new PDO($dsn, $username, $password);