java-design-patterns/data-mapper/README.md

---
layout: pattern
title: Data Mapper
folder: data-mapper
permalink: /patterns/data-mapper/
categories: Persistence Tier
tags:
 - Java
 - Difficulty-Beginner
---

## Intent
A layer of mappers that moves data between objects and a database while keeping them independent of each other and the mapper itself

![alt text](./etc/data-mapper.png "Data Mapper")

## Applicability
Use the Data Mapper in any of the following situations

* when you want to decouple data objects from DB access layer 
* when you want to write multiple data retrieval/persistence implementations

## Credits

* [Data Mapper](http://richard.jp.leguen.ca/tutoring/soen343-f2010/tutorials/implementing-data-mapper/)
Intent++ 2016-04-06 13:14:10 +05:30			`---`
			`layout: pattern`
			`title: Data Mapper`
			`folder: data-mapper`
Fix permalink to represent its current dir Otherwise the picture cant be found, as the jekyll build process will put this file in a 'dm' directory and the other stuff like resources in a 'data-mapper' directory (because resources dont have permalink specified they are served static) 2016-04-24 12:58:38 +02:00			`permalink: /patterns/data-mapper/`
Intent++ 2016-04-06 13:14:10 +05:30			`categories: Persistence Tier`
			`tags:`
			`- Java`
			`- Difficulty-Beginner`
			`---`

			`## Intent`
			`A layer of mappers that moves data between objects and a database while keeping them independent of each other and the mapper itself`

			`![alt text](./etc/data-mapper.png "Data Mapper")`

			`## Applicability`
			`Use the Data Mapper in any of the following situations`

Applicability++ 2016-04-06 13:18:42 +05:30			`* when you want to decouple data objects from DB access layer`
			`* when you want to write multiple data retrieval/persistence implementations`
Intent++ 2016-04-06 13:14:10 +05:30
			`## Credits`

			`* [Data Mapper](http://richard.jp.leguen.ca/tutoring/soen343-f2010/tutorials/implementing-data-mapper/)`