Returned values

A query should return entities of the type which is specified at the moment of creating a datasource. In case of declarative creation, the entity type is specified in the class attribute of an XML element, if DsBuilder is used – in the setJavaClass() or setMetaClass() method.

For example, a query of the datasource of the Customer entity may look as follows:

select c from sales$Customer c


select o.customer from sales$Order o

A query cannot return single attributes or aggregates, for example:

select c.id, c.name from sales$Customer c /* invalid – returns single fields, not the whole Customer object */

If you need to execute a query which returns scalar values or aggregates and to display the results in visual components using standard data binding, use Value Datasources.