Implementing EAV pattern with Hibernate for User -> Settings relationship
- by Trevor
I'm trying to setup a simple EAV pattern in my web app using Java/Spring MVC and Hibernate. I can't seem to figure out the magic behind the hibernate XML setup for this scenario.
My database table "SETUP" has three columns:
user_id (FK)
setup_item
setup_value
The database composite key is made up of user_id | setup_item
Here's the Setup.java class:
public class Setup implements CommonFormElements, Serializable {
private Map data = new HashMap();
private String saveAction;
private Integer speciesNamingList;
private User user;
Logger log = LoggerFactory.getLogger(Setup.class);
public String getSaveAction() {
return saveAction;
}
public void setSaveAction(String action) {
this.saveAction = action;
}
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
public Integer getSpeciesNamingList() {
return speciesNamingList;
}
public void setSpeciesNamingList(Integer speciesNamingList) {
this.speciesNamingList = speciesNamingList;
}
public Map getData() {
return data;
}
public void setData(Map data) {
this.data = data;
}
}
My problem with the Hibernate setup, is that I can't seem to figure out how to map out the fact that a foreign key and the key of a map will construct the composite key of the table... this is due to a lack of experience using Hibernate. Here's my initial attempt at getting this to work:
<composite-id>
<key-many-to-one foreign-key="id" name="user" column="user_id" class="Business.User">
<meta attribute="use-in-equals">true</meta>
</key-many-to-one>
</composite-id>
<map lazy="false" name="data" table="setup">
<key column="user_id" property-ref="user"/>
<composite-map-key class="Command.Setup">
<key-property name="data" column="setup_item" type="string"/>
</composite-map-key>
<element column="setup_value" not-null="true" type="string"/>
</map>
Any insight into how to properly map this common scenario would be most appreciated!
