File APIs for Java Developers
Manipulate DOC, XLS, PPT, PDF and many others from your application.
The moose likes OO, Patterns, UML and Refactoring and the fly likes One big DAO or a DAO per entity? Big Moose Saloon
  Search | Java FAQ | Recent Topics | Flagged Topics | Hot Topics | Zero Replies
Register / Login

Win a copy of Head First Android this week in the Android forum!
JavaRanch » Java Forums » Engineering » OO, Patterns, UML and Refactoring
Bookmark "One big DAO or a DAO per entity?" Watch "One big DAO or a DAO per entity?" New topic

One big DAO or a DAO per entity?

Otis Onesh

Joined: Jul 04, 2013
Posts: 6
I have seen some discussions on the internet on this subject - most were 2-3 years old - and the results are inconclusive. Are there any suggestions on how to do it nowadays with jpa and all?
Jeanne Boyarsky
author & internet detective

Joined: May 26, 2003
Posts: 32301

Welcome to CodeRanch!

I prefer to keep to one DAO per entity. Sometimes when the entities are closely related, I don't though. Or if I have reporting type queries that span a lot of tables.

In other words "it depends" which is why you aren't finding anything conclusive.

[OCA 8 book] [Blog] [JavaRanch FAQ] [How To Ask Questions The Smart Way] [Book Promos]
Blogging on Certs: SCEA Part 1, Part 2 & 3, Core Spring 3, OCAJP, OCPJP beta, TOGAF part 1 and part 2
Sujeeth Pakala
Ranch Hand

Joined: Mar 24, 2009
Posts: 99
Hello Otis,

To keep it simple : Use one DAO per entity.
To take advantage of Object oriented programming (ad to have fun !) : Generalise the CRUD ooperations using Abstraction. This way, your DAO class should be able to perform persistent opertaions on any type of entity

Good Luck !

Regards, Sujeeth Pakala
SCJP, SCWCD, SCBCD, ICAD, XML Master Basic, Certified SOA Professional
I agree. Here's the link:
subject: One big DAO or a DAO per entity?
It's not a secret anymore!