1. 24/1/20081 Architecture of multiple databases integration

2. 24/1/20082 Data Integration Concepts Data semantics define the relationships between data for users’ data requirements. Data semantics are presented in database conceptual schema such as EER model and DTD Graph. Only relevant data can be integrated for an application. Data relevance depends on users’ data requirements for an application. Data consistency are the standard of data domain value and format. Inconsistent data must be transformed before data integration. User supervision means users input for users’ data requirements, and which are for database design and schema integration

3. 24/1/20083 Schema integration of EER models Begin For each existing database do Begin If its conceptual schema does not exist then reconstruct its EER model by reverse engineering; For each pair of existing databases’ EER models schema A and schema B do begin resolve semantic conflicts between EER model A and EER model B;/step1/ Merge classes between EER model A and EER model B; /*step2*/ Merge relationships between EER model A and EER model B; /*step3*/ end

4. 24/1/20084 Step 1 Resolve conflicts among EER model Resolve conflicts on synonyms and homonyms (note: Class a and Class b are synonyms, Attribute x are homonyms)

5. 24/1/20085 Example

6. 24/1/20086 Resolve conflicts on data types

7. 24/1/20087 Example

8. 24/1/20088 Resolve conflicts on key

9. 24/1/20089 Example

10. 24/1/200810 Resolve conflicts on cardinality

11. 24/1/200811 Example

12. 24/1/200812 Resolve conflicts on weak entity

13. 24/1/200813 Example

14. 24/1/200814 Resolve conflicts on subtype entity

15. 24/1/200815 Example

16. 24/1/200816 Step 2 Merge entities Merge classes by Union

17. 24/1/200817 Example

18. 24/1/200818 Merge EER models by Generalization

19. 24/1/200819 Example

20. 24/1/200820 Merge EER models by Subtype Relationship

21. 29/1/200821 Example

22. 28/1/200822 Merge entities by Aggregation

23. 24/1/200823 Example

24. 24/1/200824 Merge entities by categorization

25. 24/1/200825 Example

26. 24/1/200826 Merge entities by Implied Binary Relationship

27. 24/1/200827 Example

28. 24/1/200828 Step 3 Merge relationships Merge relationships by subtype relationship

29. 24/1/200829 Example

30. 24/1/200830 Merge relationships by overlap generalization

31. 24/1/200831 Example

32. 24/1/200832 Absorbing Lower degree Relationship into a Higher degree Relationship

33. 24/1/200833 Example

34. 24/1/200834 Case Study: In a bank, there are existing databases with different schemas: one for the customers, another for the mortgage loan contracts and a third for the index interest rate. However, there is a need to integrate them together for an international banking loan system.

35. 24/1/200835 Step 2 Merge entities by Implied binary relationship and Generalization Since data ID# appears in entity Mortgage Loan Contract and entity Customer, they are in one-to-many cardinality with foreign key on the “many” side. Since Fixed and Index Interest Rate both have the same key, Interest_effective_date, they can be generalized disjointed as either fixed or index rate.

36. 24/1/200836 Thus, we can derive cardinality from the implied relationship between these entities, and integrate the two schemas into one EER model.

37. 24/1/200837 Reading assignment “Information Systems Reengineering and Integration” by Joseph Fong, published by Springer Verlag, 2006, pp. 282-310.

38. 24/1/200838 Review question 3 Can two Relational Schemas be integrated into one Relational Schema? Explain your answer. Which steps need user supervision for integrating two Extended Entity Relationship Models into one Extended Entity Relationship Model? Explain your answer.

39. 24/1/200839 Tutorial question 3 Provide an integrated schema for the following two views which are merged to create a bibliographic database. During identification of correspondences between the two views, the users discover the followings: RESEARCHER and AUTHOR are synonyms, CONTRIBUTED_BY and WRITTEN_IN are synonyms, ARTICLES belongs to a SUBJECT. ARTICLES and BOOK can be generalized as PUBLICATION. Hints: Given two subclass entities have same relationship(s). The two subclasses entities can be generalized into a superclass entity and the subclass relationship(s) can also be generalized into a superclass relationship..