/**
* Fetch the next incremental value for the specified field.
* If no field name is specified, it will use the primary key
* field by default.
*/
public function next ($field = false) {
if ($field === false) {
$field = $this->key;
}
$res = DB::shift (
'select (' . Model::backticks ($field) . ' + 1)' .
' from ' . Model::backticks ($this->table) .
' order by ' . Model::backticks ($field) . ' desc' .
' limit 1'
);
if (! $res) {
return 1;
}
return $res;
}
/**
* Performs a batch of changes wrapped in a database transaction.
* The batch `$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
$sql = 'insert into `' . $this->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');
}
