How do I loop through the mysql resultset in fatfr

Question

I am new to the php fat-free framework, and I am trying figure out how to loop through my mysql query results, or better yet, get it as an associative array (for learning purposes only).

What I did so far is

while(!$users->dry()){
   array_push($user_assoc,$users->cast());
   $users->next();
}

This works, but I was wondering if there is a better way of doing this? Also how do I setup a error handler? I mean how do I check if the query had any errors (i.e. fat-free equivalent of mysql_error())?

Answer 1

You're already using the correct way. At least if you want to use the mapper. By using the SQL class directly, an associative array is returned. Mostly everything related to that is described here http://fatfreeframework.com/databases#querying-the-database

$result = $db->exec('SELECT * FROM users'); 
print_r($result);

If you're looking for errors or you want to know what has been executed, use $db->log();. http://fatfreeframework.com/databases#profiling

Answer 2

DB querying

There are 3 variants to loop through db results:

Without mapper:

Execute a SQL query and fetch the result set as an array of associative arrays:

$users = $db->exec('SELECT * FROM users');
foreach($users as $user)
  echo $user['name'];//associative array

With mapper->load:

Fetch mapper rows one by one (your method):

$user=new \DB\SQL\Mapper($db,'users');
$user->load('');
while(!$user->dry()) {
  echo $user->name;//db mapper
  $user->next();
}

With mapper->find:

Fetch the result set as an array of mappers:

$mapper=new \DB\SQL\Mapper($db,'users');
$users=$mapper->find('');
foreach($users as $user)
  echo $user->name;//db mapper

DB error handling

\DB\SQL is a subclass of PDO so it can throw catchable PDO exceptions. Since these are disabled by default, you need to enable them first. This can be done in 2 different ways:

• at instantiation time, for all transactions:

  $db = new \DB\SQL($dsn, $user, $pwd, array( \PDO::ATTR_ERRMODE => \PDO::ERRMODE_EXCEPTION ));

• later on in the code, on a per-transaction basis:

  $db->setAttribute(\PDO::ATTR_ERRMODE, \PDO::ERRMODE_EXCEPTION);

Once PDO exceptions are enabled, just catch them as other exceptions:

try {
  $db->exec('INSERT INTO mytable(id) VALUES(?)','duplicate_id');
} catch(\PDOException $e) {
  $err=$e->errorInfo;
  //$err[0] contains the error code (23000)
  //$err[2] contains the driver specific error message (PRIMARY KEY must be unique)
}

This also works with DB mappers, since they rely on the same DB\SQL class:

$db=new \DB\SQL($dsn,$user,$pwd,array(\PDO::ATTR_ERRMODE=>\PDO::ERRMODE_EXCEPTION));
$mytable=new \DB\SQL\Mapper($db,'mytable');
try {
  $mytable->id='duplicate_id';
  $mytable->save();//this will throw an exception
} catch(\PDOException $e) {
  $err=$e->errorInfo;
  echo $err[2];//PRIMARY KEY must be unique
}