Grails下载复合id

Question

我需要填充搜索功能的下拉列表。我遇到了一些困难，因为该表具有复合ID。我相信我必须引用两个外键但不确定如何。

Oracle 11g本地和READ ONLY gGrails 2.3.3

这是我的带有复合键的域

static belongsTo = [trustee:Trustee, committees:Committees]//

    static constraints = {          
        position nullable:true
        type nullable:true
    }

    static mapping = {
        table 'BOT_TRUSTEE_COMMITTEES'
        version false
        id composite: ['trustee','committees'] 
        trustee column:'TRUSTEE_ID'
        committees column: 'COMMITTEE_ID'

        position column:'POSITION'
        type column:'TYPE'          
    }

以下是调用我的下拉列表的视图模板

<tr>
    <td>
        <label for="hospital">
            <g:message code="hospitals.hospitalName.label" default="Hospital:" />       
        </label>
    </td>
    <td>
        <g:select name="hospitalId" from="${Hospitals.list()}" optionKey="id" required="" optionValue="hospitalName" noSelection="['null':'-Choose a hospital-']"/>
    </td>
</tr>

<!-- Committee drop down list -->
<tr>
    <td>
        <label for="committee">
            <g:message code="committees.description.label" default="Committee:" />      
        </label>
    </td>
    <td>
        <g:select name="committeesId" from="${Committees.list()}" optionKey="id" required="" optionValue="committeeName" noSelection="['null':'-Choose a committee-']" />
    </td>
</tr>

<!-- Type drop down list -->
<tr>
    <td>
        <label for="type">
            <g:message code="membership.type.label" default="Type:" />      
        </label>
    </td>
    <td>
        <!-- input drop down list for type here -->
        <g:select name="trusteeType" from="${TrusteeMembership.list()}" optionKey="id" required="" optionValue="type" noSelection="['null':'-Please select one-']"/>

    </td>
</tr>