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

---
layout: pattern
title: Data Mapper
folder: data-mapper
permalink: /patterns/data-mapper/
categories: Architectural
language: en
tags:
 - Decoupling
---

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

## Class diagram
![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/`
https://github.com/iluwatar/java-design-patterns-web/issues/8 Update pattern categories and tags 2019-12-13 21:09:28 +02:00			`categories: Architectural`
fix: Fixed pages showing up in wrong language (#1752) * Fix languages * Missed change for version number * Add language field for presentation * Revert change in README for double buffer Co-authored-by: Jackie Nim <=> 2021-05-19 10:49:05 -06:00			`language: en`
Intent++ 2016-04-06 13:14:10 +05:30			`tags:`
https://github.com/iluwatar/java-design-patterns-web/issues/8 Update pattern categories and tags 2019-12-13 21:09:28 +02:00			`- Decoupling`
Intent++ 2016-04-06 13:14:10 +05:30			`---`

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

#1113 Link uml-reverse-mapper created class diagrams to readme, where needed 2019-12-07 20:01:13 +02:00			`## Class diagram`
Intent++ 2016-04-06 13:14:10 +05:30			`![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/)`