Semantic Repositories are tools that combine the characteristics of database management systems (DBMS) and inference engines. Their major functionality is to support efficient storage, querying and management of structured data. One major difference to DBMS is that Semantic Repositories work with generic physical data models (e.g. graphs). This allows them to easily adopt updates and extensions in the schemata, i.e. in the structure of the data. Another difference is that Semantic Repositories use ontologies as semantic schemata, which allows them to automatically reason about the data.
The two principle strategies for rule-based reasoning are:
Imagine a repository, which performs total forward-chaining, i.e. it tries to make sure that after each update to the KB, the inferred closure is computed and made available for query evaluation or retrieval. This strategy is generally known as materialization.