Bridging the Gap between OWL and Relational Databases

1
Bridging the Gap between OWL and Relational
Databases

• Yan Qi
• CSE 494

2
Motivation

• Integrity Constraints (ICs) in Relation DB
• Data reasoning (checking db integrity)
• Schema reasoning (computing query subsumption)
• Integrity Constraints (ICs) in OWL
• e.g. an inclusion dependency, stating that a
  social security number must exist for each
  person.
• In RDB, its interpreted as a check
• In OWL, an existential restriction, (not an error
  but an inference).

3
Analysis and Solution

• OWL
• Description Logic knowledge base
• TBox schema part
• ABox data part
• Extended DL knowledge bases
• Divide the axioms in TBox as
• Standard axioms imply new facts
• Constraint axioms check if all necessary
  information is derivable.

4
Criticism

• ICs in OWL can be interpreted as the same way as
  that in Relation DB.
• Answering unions of positive conjunctive queries
  ICs can be disregarded if they are satisfied.
• Query processing could be optimized.
• One concern is the complexity of the
  implementation of such a OWL reasoner, and the
  time cost of the process of reasoning.
• Think about large OWL file.

5
Related to our class

• A fairly complete comparison of OWL and RDB.
• Good understanding of ontology
• and integrity constraints
• OWL vs. Relational DB
• Schema Language
• Interpreting the Schema
• Domains and Typing
• Schema Reasoning
• Query Answering
• Constrain Checking

6

• What is the problem that the paper is addressing?
• Why is the problem interesting?

• What is the solution that the authors propose?

• How is it related to what we learned in the class?

• What is your criticism of the solution presented?