Solar_Sql begins in auto-commit mode, which means that all queries are committed to the database as they are executed.
If you want leave auto-commit mode and start a transaction, call Solar_Sql_Adapter::begin(). Then, after you save the transaction using Solar_Sql_Adapter::commit() or cancel it using Solar_Sql_Adapter::rollback(), Solar_Sql returns to auto-commit mode until you begin another transaction.
Here's a simple example:
$sql = Solar::factory('Solar_Sql');
$sql->begin(); // autocommit turns off
try {
// do stuff, and then ...
$sql->commit(); // autocommit turns on
} catch (Exception $e) {
$sql->rollback(); // autocommit turns on
}