I want to allow the user to add custom attributes to various entities at runtime. For example, they can add a new field "Birthday" to an "Employee" entity. I want to map these custom attributes (which will likely be stored as name/value pairs) to some separate tables that will store custom attributes. Is there any way to allow mapping of such custom attributes to tables that store custom properties? When I load Employee I want to load both the columns from the Employee table and the rows/columns for the custom attributes from the other table.

Is there any other way to easily achieve implementation of custom attributes at run time?

Thanks,

Sunondo

Use a collection (map, set, list, whatever), and have the attrbiute table have the employee id, attribute name and attribute value columns. I'd recommend the map element, with key = emplyoee id, map-key = attribute name, element = attribute value.

If you want to restrict the custom attribute names without using a custom attrbiute name table (for referential integrity), you can make use of dynamic components. See section 8.5 of the ref docs.