In the case of nested transactions, if the transaction is a parent transaction, committing the parent transaction causes all unresolved children of the parent to be committed. In the case of nested transactions, if the transaction is a child transaction, its locks are not released, but are acquired by its parent. Although the commit of the child transaction will succeed, the actual resolution of the child transaction is postponed until the parent transaction is committed or aborted; that is, if its parent transaction commits, it will be committed; and if its parent transaction aborts, it will be aborted.
All cursors opened within the transaction must be closed before the transaction is committed. If there are cursor handles open when this method is called, they are all closed inside this method. And if there are errors when closing the cursor handles, the transaction is aborted and the first such error is returned.