K2 takes an object-oriented approach to mediation. You define the objects over which you want to issue queries, then describe how the data sources will be used to populate the objects. You do all this through a simple language called K2MDL (K2 Mediator Definition Language). K2MDL is a hybrid of ODMG-standard ODL and OQL, which means it is accessible to anyone who has experience with object-oriented modeling and querying. Little or no programming experience is required.
This document assumes that all of the data sources among which you wish to mediate are already connected to K2. If this is not the case, you need to either use the built-in data drivers to connect to your sources, or develop your own.
Once K2 can talk to the data sources you need, the mediator generation process can proceed through the following steps:
Creating the object model against which you will issue queries.
Defining the extents of the classes you've described.
Populating the attributes of the classes with data from your data sources.
Connecting the classes in your model by establishing relationships between them.
Using your mediator to issue queries against the underlying data sources.
The first step in building a mediator is creating an object model.