Filter in form

void  init()
{
    str a;
    Query                   queryVersion;
    QueryBuildDataSource    qbdsVersion;
    QueryBuildRange         qbr;

    ;

    callerDrawingVersion    = element.args().record();
    if(!callerDrawingVersion)
        throw error("Function is called incorrectly.");
    super();
    queryVersion = new query();
    qbdsVersion      = queryVersion.addDataSource(Tablenum(SCA_DrawingVersion));
    qbdsVersion.addRange(fieldnum(SCA_DrawingVersion, Drawingcode)).value(queryvalue(callerDrawingVersion.DrawingCode));
    SCA_DrawingVersion_ds.query(queryVersion);
    SCA_DrawingVersion_ds.executeQuery();

}