A database system is able to perform efficient execution of insert-select, join-delete,
or join-update requests. The database system has plural access modules to manage
access of respective portions of data in a storage of the database system. If certain
predefined criteria are satisfied, the insert-select, join-delete, or join-update
request can be executed by performing a single-access module merge and/or merge-delete
step on a single one of the access modules with row-level locks (e.g., row-hash locks).