Once you have a query object built, either through a parameterized statement or through the builder, you must then execute()
the query and retrieve the results. Depending on the query type used, the results returned will vary.
DB::select will return a Database_Result object which you can then iterate over. This example shows how you can iterate through the Database_Result using a foreach.
$results = DB::select()->from('users')->where('verified', '=', 0)->execute();
foreach($results as $user)
{
// Send reminder email to $user['email']
echo $user['email']." needs to verify his/her account\n";
}
as_object()
and as_assoc()
When iterating over a result set, the default type will be an associative array with the column names or aliases as the keys. As an option, before calling execute()
, you can specify to return the result rows as an object by using the as_object()
method. The as_object()
method takes one parameter, the name of the class of your choice, but will default to TRUE which uses the stdClass
. Here is the example again using stdClass
.
$results = DB::select()->from('users')->where('verified', '=', 0)->as_object()->execute();
foreach($results as $user)
{
// Send reminder email to $user->email
echo $user->email." needs to verify his/her account\n";
}
The method as_assoc()
will remove the object name and return the results set back to an associative array. Since this is the default, this method is seldom required.
as_array()
Sometimes you will require the results as a pure array rather than as an object. The Database_Result
method as_array()
will return an array of all rows.
$results = DB::select('id', 'email')->from('users')->execute();
$users = $results->as_array();
foreach($users as $user)
{
echo 'User ID: '.$user['id'];
echo 'User Email: '.$user['email'];
}
It also accepts two parameters that can be very helpful: $key
and $value
. When passing a value to $key
you will index the resulting array by the column specified.
$results = DB::select('id', 'email')->from('users')->execute();
$users = $results->as_array('id');
foreach($users as $id => $user)
{
echo 'User ID: '.$id;
echo 'User Email: '.$user['email'];
}
The second parameter, $value
, will reference the column specified and return that value rather than the whole row. This is particularly useful when making <select>
dropdowns.
$results = DB::select('id', 'name')->from('users')->execute();
$users = $results->as_array('id','name');
// Show a dropdown with all users in it.
echo Form::select('author', $users)
To return a non-associative array, leave $key
as NULL and just pass a $value
.
$results = DB::select('email')->from('users')->execute();
$users = $results->as_array(NULL, 'email');
foreach($users as $email)
{
echo 'User Email: '.$email;
}
get()
Sometime you only want a single value from a query. The get()
method returns the value of the named column from the current row. The second parameter, $default
, is used to supply a default value when the result is NULL.
$total_users = DB::select(array(DB::expr('COUNT(`username`)'), 'total_users'))->from('users')->execute()->get('total_users', 0);
cached()
The mysql database driver returns a Database_Result
that works with a MySQL Resource data type. Since this resource lives outside of PHP environment, it can't be serialized which means it also can't be cached. To get around this the Database_Result
object has the cached()
method that returns a Database_Result_Cached
object of the result set. The Database_Result_Cached
can be serialized and cached, but can take up more memory.
NOTE: Currently, the PDO diver always returns a class of Database_Result_Cached
, so cached()
just returns itself.
The cached()
function doesn't actually do any caching, it simply returns the result in a way that can be serialized and cached. You will need to use the Cache Module or some other caching method.
count()
The Database_Result
object implements the Countable
Interface. The method count()
returns the total row count in the result set.
NOTE: This is the count of the current result set, not a count of how many records are in the database. This is important to point out especially when using limit()
and offset()
in your query.
For a complete list of methods available when working with a result set see Database_Result.
DB::insert returns an array of two values: the last insert id and the number of affected rows.
$insert = DB::insert('tools')
->columns(array('name', 'model', 'description'))
->values(array('Skil 3400 10" Table Saw', '3400', 'Powerful 15 amp motor; weighs just 54-pounds'));
list($insert_id, $affected_rows) = $insert->execute();
DB::update and DB::delete both return the number of affected rows as an integer.
$rows_deleted = DB::delete('tools')->where('model', 'like', '3400')->execute();