Hibernate version:3.2.6

Hi,

I have a database table EMP_TABLE like :
EMP_ID | KEY | VALUE
100 | EMP_NAME | John Scott
100 | CITY | NEW YORK
100 | COUNTRY | USA
240 | EMP_NAME | Shane Watt
240 | COUNTRY | CAN
300 | COUNTRY | USA

How should I write hibernate mappings for this table so that I can get the employee details & also save/update it, using following class ?


Mapping :



Any kind of clue, help is appreciated.

I don't know if there is any direct way of doing what you want.

Instead you could declare a Map<String,String> in your mapping file.

Using annotations this would be as follows -

@CollectionOfElements(fetch=FetchType.EAGER)
@JoinTable(name = "METADATA", joinColumns = @JoinColumn(name = "EMP_ID"))
@MapKey(columns={@Column(name="KEY", nullable = false)})
@Column(name = "VALUE", nullable = false)
private Map<String, String> getMetaData() {
return _metaData;
}


After defining this mapping - you can use getters and setters for city,name, etc to directly get or set properties from this map.
eg -
publci String getCity() {
return _metaData.get("City");
}

Of-course disadvantage would be that you are fetching entire map and not just the few properties that you are interested in and there is an extra join being done with a separate map table.