Metadata

Strictly speaking, meta-data is data about data. That is, a way to describe data (specify its semantics, relationships with other data, and so on).

Archipelago uses 3 types of metadata :

1. the database schema, that describes the structure of some existing database and the way it can be accessed.
2. that meta model, that describes the structure of the data the user wants to handle. That is, the structure of the view through which concrete data are to be viewed.
3. the database mapping, that describes the mapping between the 2.

The reference implementation of the Archipelago project will provide :

• databases schemas for several known databases
• a sample meta-model
• mappings from those known databases to this meta model