Web-based Schema Integration System

1. Web-based Schema Integration System A research on Data Integration Supervisor: Dr Le Minh Duc Student: Tran Thi Linh

2. Web-based Schema Integration System Outline • Schema Integration Overview • Web-based Schema Integration System • System Architecture Overview • Key functions in the system. • Display schemas • Integration Performing • Display Integration output

3. Web-based Schema Integration System Schema Integration Overview Schema integration problem is dealing with the heterogeneity in database management. • In database management, the designers use various forms to structure and model the database. (flat files, semi-structured models such as ERD, relational, UML, XML) • On demand of merging different databases, we need to integrate their schema models into a single schema first.

4. Web-based Schema Integration System Schema Integration Overview • Examples of various forms of heterogeneity: • Entity-Relationship with Constructs: Entity – attribute – relationships and constraints (i.e. cardinality)

5. Web-based Schema Integration System Schema Integration Overview • The various forms of heterogeneity: • Relational Model with Constructs: Table – Field– Keys

6. Web-based Schema Integration System Schema Integration Overview • The various forms of heterogeneity: • UML

7. Web-based Schema Integration System Schema Integration Overview • AutoMed Data Integration System: • A desktop-based application • It is a framework comprising of a graphical tool (Swing GUI) and a programmer API for conducting Data Integration Tasks • Its features • Wrapping schema from relational databases • Representing schema in high level graph based model • Using a common data model named Hyper-graph based model (HDM) • HDM: low level data model comprising of 3 primitive constructs for representing a model: Nodes – Edges - Constraints • Provide a data integration engine which is implemented in Java that supports query processing over schema

8. Web-based Schema Integration System Schema Integration Overview • AutoMed Data Integration System • » Could we use it over the Internet, i.e. running it on the web?

9. Web-based Schema Integration System Web-based Schema Integration System • Overall idea: originate from AutoMed • Create a schema integration that runs on the Web • Using AutoMed API as the schema integration engine. (i.e. AutoMed serves as a web server)

10. Web-based Schema Integration System Web-based Schema Integration System • System Architecture Overview • AutoMed system architecture

11. Web-based Schema Integration System • Our proposed web-based schema integration system architecture Web browsers: send request for schema integration functions to server Web Server: where AutoMed Engine is placed, process requests, then send the response » we define a data structure for storing schemas’ information and the Draw function using this information to represent input and output of schema integration process »To manipulate with the schemas and the models that are stored in the repository, we use AutoMed API. That why we said using AutoMed API as schema engine for our system

12. Web-based Schema Integration System Web-based Schema Integration System • The key functions in the system • Display schemas • Performing integration • Display integration output Note that: our proposed system focuses on 2 challenges to deal with Schema Integration problem • The heterogeneity in database • How to perform it on the Web

13. Web-based Schema Integration System Display Schemas • In AutoMed: • Represent schemas in graphs that nearly have the same view as the traditional view of specific models • ERD:

14. Web-based Schema Integration System Display Schemas • In AutoMed: • Represent schemas in graphs that nearly have the same view as the traditional view of specific models • Relational:

15. Web-based Schema Integration System Display Schemas • In AutoMed: • Represent schemas in graphs that nearly have the same view as the traditional view of specific models • UML:

16. Web-based Schema Integration System Display Schemas • Our solutions: • Using a common layout for all kinds of models: A graph of circle with points are schema objects such as: entity, attribute, relationship, relation, fields … • To display schemas on web: using SVG/ JavaScript

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18. Web-based Schema Integration System For UML

19. Web-based Schema Integration System Integration Performing • There are some schemas(let’s call source schemas), we need integrate them into a single schema (let’s call global schema) which covers all schemas. From this single schema we can query data from all source schemas. • To make it simple: • performing integration is the process of mapping a schema to a global schema. (with n source schemas we do it n-times)

20. Web-based Schema Integration System Integration Performing • Steps/ activities: • Compare schemas: • Determine the correspondences among concepts between schemas • Detect the conflicts between schemas • Conforming schemas: • Resolve conflicts, align schemas to make them compatible • To do it: apply transformations to schema: adding more, deleting, renaming schema objects … • » basically, we call this step as mapping schemas

21. Web-based Schema Integration System Integration Performing • In AutoMed: • Using bidirectional pathway as Both-as-view mapping technique. • Transform source schemas into a common hyper-graph data model (HDM) • HDM is a low level model. It comprises of 3 primitive constructs for representing a schema model: Nodes – Edges - Constraints • There are mapping rules to define how to map these modeling constructs into those in other high level data models. • For example, Nodes are mapped to Entity in Entity-Relationship model, Edge is a combination of an entity and a relationship • In the AutoMed, the transformation models into HDM models is done automatically.

22. Web-based Schema Integration System Integration Performing • Our solutions: • Visually compare schemas on the web: display 2 schemas at the same time • Schemas are displayed in a common layout • To create mappings for schema: user interacts with the schema objects to define transformation steps

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24. Web-based Schema Integration System Display Integration Output • Showing mappings or transformation user created • In AutoMed: • Transformation pathway is represented as a directed graph (called a network) • No comparative view over 2 or more pathways: • Set of pathways between 2 schemas in case of different ways for defining transformation • Our solutions: • Using the common layout stated before for both schema and pathway. • Using concentric circles with different radii for a set of pathways between 2 schemas • Using a system of circles that share the a common point for 2 or more pathways connected to a given schema.

25. Web-based Schema Integration System Display Integration Output • Showing mappings or transformation user created • In AutoMed:

26. Web-based Schema Integration System Display Integration Output • Showing mappings or transformation user created • Our solutions:

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30. Thank you for your attention!