Data access object
lastmod 2026-11-10created 2017-11-192 edits
A Data access object (DAO) is a design pattern that separates access logic for a database or other storage into a dedicated object. Business logic calls only the save, retrieve, update, and delete methods that the DAO provides and does not know about SQL or the kind of storage, so it is easy to change the storage method or replace the DAO with a fake object in tests. It was widely used in Java EE environments and is compared with ORM and the repository pattern.