Question

I have the next database schema:

CREATE TABLE A (id INTEGER);
CREATE TABLE Single_Values (fk_a INTEGER, fk_b INTEGER, value VARCHAR(255));
CREATE TABLE List_Values (fk_a INTEGER, fk_b INTEGER, value VARCHAR(255));
CREATE TABLE B (id INTEGER, name VARCHAR(255));

And i have next object model (schematic):

class B{
    Integer id;
    String name;
}

class SingleValue extends B{
    String value;
}

class ListValues extends B{
    List<String> values;
}

class A{
    Integer id;
    Map<Integer, SingleValue> singleMap;
    Map<Integer, ListValues> listMap;
}

I made next ​​a mapping to the single value’s map:

<class name="B">
   <id name="id"/>
   <property name="name"/>
   <joined-subclass name="SingleValue">
       <key column="fk_b"/>
       <property name="value"/>
   </joined-subclass>
</class>
<class name="A">
    <id name="id"/>
    <map name="singleMap" table="Single_Values">
        <key column="fk_a"/>
        <map-key column="fk_b"/>
        <one-to-many class="B"/>
    </map>
</class>

And I stucked with the mapping of listMap. Any help with mapping this will be appreciated.

Answer 1

Do not use Maps, use Lists. If you want to look up Map-style either use a query or build a temporary map after getting the list from the database. Also, @annotations would make your life more easy?