---
layout: pattern
title: Data Access Object
folder: dao
permalink: /patterns/dao/
categories: Architectural
tags:
 - Data access
---

## Intent
Object provides an abstract interface to some type of database or
other persistence mechanism.

## Class diagram
![alt text](./etc/dao.png "Data Access Object")

## Applicability
Use the Data Access Object in any of the following situations

* when you want to consolidate how the data layer is accessed
* when you want to avoid writing multiple data retrieval/persistence layers

## Credits

* [J2EE Design Patterns](https://www.amazon.com/gp/product/0596004273/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0596004273&linkCode=as2&tag=javadesignpat-20&linkId=48d37c67fb3d845b802fa9b619ad8f31)