/**
* Performs a batch of changes wrapped in a database transaction.
* The batch `$task` can be an array of items to insert at once,
* or a closure function that executes a series of tasks and
* performs whatever logic necessary. If any insert fails, or if
* the function returns false, the transaction will be rolled
* back, otherwise it will be committed. For databases that support
* it, records will be inserted using a single SQL insert statement
* for greater efficiency.
*/
public static function batch ($tasks) {
DB::execute ('begin');
if ($tasks instanceof Closure) {
if ($tasks () === false) {
self::$batch_error = DB::error ();
DB::execute ('rollback');
return false;
}
} elseif (is_array ($tasks)) {
// Check the driver type, because SQLite doesn't support
// multiple row inserts
$db = DB::get_connection (1);
if (! $db) {
self::$batch_error = 'No database connection';
return false;
}
if ($db->getAttribute (PDO::ATTR_DRIVER_NAME) === 'sqlite') {
$class = get_called_class ();
foreach ($tasks as $task) {
$o = new $class ($task);
if (! $o->put ()) {
self::$batch_error = $o->error;
DB::execute ('rollback');
return false;
}
}
return DB::execute ('commit');
}
// Build the multi-row insert statement
$class = get_called_class ();
$o = new $class;
$sql = 'insert into `' . $o->table . '` (';
$data = array ();
// Figure out how many placeholders are needed per record
$ins = array ();
$len = count ($tasks[0]);
for ($i = 0; $i < $len; $i++) {
$ins[] = '?';
}
// Add fields to statement
$sql .= join (', ', Model::backticks (array_keys ($tasks[0]))) . ') values ';
$sep = '';
// Add each record to the statement
foreach ($tasks as $task) {
$data = array_merge ($data, array_values ($task));
$sql .= $sep . '(' . join (', ', $ins) . ')';
$sep = ', ';
}
if (! DB::execute ($sql, $data)) {
self::$batch_error = DB::error ();
DB::execute ('rollback');
return false;
}
}
return DB::execute ('commit');
}
