# Entity EJB

- Purpose
- Structure
- Applications
- Consequences

## Purpose

- To express/save business domain data and configure relationships with databases.
- To enable data synchronization and transaction services.

## Structure

- EntityBean : EJB for expressing business-related data.
- Entity : Remote Interface for EntityBean.
- EntityHome : Home Interface for EntityBean.
- EntityPK : Class for identifying EntityBean.

## Applications

- Can be used for applying Object-Relation Mapping to business domain data.
- Can be used for assuring the synchronization, transaction and integrity of the data.

## Consequences

- Data Access layer expresses persistent objects.
- Data synchronization and transaction integrity can be guaranteed by delegating to containers.
- In case of data structure change, only the related EntityBeans need to be modified.