Select data from database and update it PHP/PDO - php

Question

I need to make a PHP code that gets data from server, updates it and echos that updated data to user. I am beginner with PHP so I have no idea how to do this. This is the code I have have now.
So how do I change the code to make it update data ?
<?php
include 'config.php';
$ID = $_GET['ID'] ;
$sql = "select * from table where ID = \"$ID\" and condition = false ";
// This is what I need the table to be updated "Update table where where ID = \"$ID\" set condition = true" ;
try {
$dbh = new PDO("mysql:host=$dbhost;dbname=$dbname", $dbuser, $dbpass);
$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$stmt = $dbh->query($sql);
$data = $stmt->fetchAll(PDO::FETCH_OBJ);
$dbh = null;
echo '{"key":'. json_encode($data) .'}';
} catch(PDOException $e) {
echo '{"error":{"text":'. $e->getMessage() .'}}';
}
?>

Answer 1

one idea is to create a different database connection file consisting of a pdo connection and reuse it in your application. on how to do that.
in database.php you can do it like
try {
$dbh = new PDO("mysql:host=$dbhost;dbname=$dbname", $dbuser, $dbpass);
$dbh->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
} catch(PDOException $e) {
//catch the exception here and do whatever you like to.
}
and everywhere you want to use the connection you can do
require_once 'Database.php';
and some of the sample CRUD (Create, Read, Update, Delete) using PDO are.
//Create or Insert
$sth = $dbh->prepare("INSERT INTO folks ( first_name ) values ( 'Cathy' )");
$sth->execute();
//Read or Select
$sth = $dbh->query('SELECT name, addr, city from folks');
//Update
$sth = $dbh->prepare("UPDATE tablename SET col = val WHERE key = :value");
$sth->bindParam(':value', $value);
$sth->execute();
//Delete
$dbh->query('DELETE FROM folks WHERE id = 1');
you should also study about named and unnamed placeholders, to escape SQL injections etc. you can read more about PDO with a very easy to understand tutorial by nettuts here
hope this helps you.

Answer 2

Try this. I think it is along the lines of what you are looking for:
$query = "select * from table where ID = \"$ID\" and condition = false ";
$query_result = #mysql_query($query);
$query_row = mysql_fetch_assoc($query_result);
$update_query = "UPDATE table SET condition = true WHERE ID = {$row['ID']};";
if( #mysql_query($update_query) ) {
echo "Update succeeded!";
} else {
echo "Update failed!";
}

Answer 3

<?php
$ID = 1;
try {
$db = new PDO("mysql:host=$dbhost;dbname=$dbname", $dbuser, $dbpass);
$select_statement = $db->prepare('select * from table1 where id = :id and `condition` = false');
$update_statement = $db->prepare('update table1 set `condition` = true where id = :id');
$select_statement->execute(array(':id' => $ID));
$results = $select_statement->fetchAll();
$update_statement->execute(array(':id' => $ID));
echo '{"key":' . json_encode($results) .'}';
} catch(PDOException $e) {
echo '{"error":{"text":'. $e->getMessage() .'}}';
}
?>