Object Definition Language
ODL is a method of specifying the domain knowledge to the mediator system. ODL provide a mechanism to define a class of objects. Each of these classes will have a set of
- attributes - represent the data of a class;
- functions provide a means for a additional data abstraction (match face in pictorial data base)
- and/or relationships - represents how one or more classes relate to each other;
It is important to note that each mediator and wrapper subsystem must have its own ODL specification. This is necessary because
- each wrapper has its domain focused on the specific view of one data source , while
- mediator’s domain is the integrated view of all it’s underlying wrappers