/**
* Snapshot isolation is not compatible with DDL operations.
*
* @return TransactionSettings
*/
public static function GetDDLCompatibleDefaults() {
return new TransactionSettings(TRUE,
DatabaseTransactionScopeOption::Required(),
DatabaseTransactionIsolationLevel::ReadCommitted());
}
/**
* Summary of pushTransaction
* @param string $name
* @param DatabaseTransactionSettings $settings
* @throws DatabaseTransactionNameNonUniqueException
* @return void
*/
public function pushTransaction($name, $settings = NULL) {
if ($settings == NULL) {
$settings = DatabaseTransactionSettings::GetBetterDefaults();
}
if (!$this->supportsTransactions()) {
return;
}
if (isset($this->transactionLayers[$name])) {
throw new DatabaseTransactionNameNonUniqueException($name . " is already in use.");
}
$started = FALSE;
// If we're already in a transaction.
// TODO: Transaction scope Options is not working properly
// for first level transactions. It assumes that - always - a first level
// transaction must be started.
if ($this->inTransaction()) {
switch ($settings->Get_ScopeOption()) {
case DatabaseTransactionScopeOption::RequiresNew():
$this->query_direct('SAVE TRANSACTION ' . $name);
$started = TRUE;
break;
case DatabaseTransactionScopeOption::Required():
// We are already in a transaction, do nothing.
break;
case DatabaseTransactionScopeOption::Supress():
// The only way to supress the ambient transaction is to use a new connection
// during the scope of this transaction, a bit messy to implement.
throw new Exception('DatabaseTransactionScopeOption::Supress not implemented.');
}
}
else {
if ($settings->Get_IsolationLevel() != DatabaseTransactionIsolationLevel::Ignore()) {
$current_isolation_level = strtoupper($this->schema()->UserOptions()['isolation level']);
// Se what isolation level was requested.
$level = $settings->Get_IsolationLevel()->__toString();
if (strcasecmp($current_isolation_level, $level) !== 0) {
$this->query_direct("SET TRANSACTION ISOLATION LEVEL {$level}");
}
}
// In order to start a transaction current statement cursors
// must be closed.
foreach($this->statement_cache as $statement) {
$statement->closeCursor();
}
$this->connection->beginTransaction();
}
// Store the name and settings in the stack.
$this->transactionLayers[$name] = array('settings' => $settings, 'active' => TRUE, 'name' => $name, 'started' => $started);
}
