1. Chapter 2 Database Environment
Thomas Connolly, Carolyn Begg, Database System, A Practical Approach to Design Implementation and Management, 4th Edition, Addison Wesley
Pg 33 ~ 62

2. Learning Outcomes Three-Level ANSI-SPARC Architecture
Database Languages
Data Models
Functions of DBMS
Components of DBMS
Teleprocessing

3. ANSI/SPARC ANSI SPARC 1975 American National Standards Institute
Standards Planning and Requirements Committee
1975
Proposed a framework for DBS

4. Three-Level ANSI-SPARC Architecture
External level (Database Users)
Provide a view of the database tailored to a user
Data gathering
Conceptual level (Database Designer)
Deals with the organization of data as a whole
Constraints and security
Entity-relationship diagram
Normalization
Internal level (System Designer)
Deal with physical storage of data
Storage, index, compression, & encryption
File organization

5. Database Schemas
Database schema (intension) & database instance (extension)
External schemas (subschema)
Conceptual schema (database schema)
Internal schema

6. Mapping Translate information from one level to the next
External/conceptual mapping
Conceptual/internal mapping
Provide data independence

7. Data Independence Logical data independence Physical data independence
Conceptual level changed shouldn’t affect external levels
Physical data independence
Change to internal level shouldn’t affect conceptual level

8. ANSI/SPARC Architecture

9. Database Languages Data Definition Language (DDL)
Structured Query Language (SQL)
Data Manipulation Language (DML)
Procedural DML
Non-procedural DML
Query-by-Example (QBE)
Fourth-Generation Language
Form, report, graphics, & application generators

10. Data Models Definition Types
Integrated concept for describing data, relationships and constraints
Types
Object-based data models
Record-based data models
Physical data models (internal structure, ordering, & paths)

11. Object-Based Data Models
Entity-relationship
Entity, attribute, relationship
Usage: documentation
Object-oriented
Object, class, subclass, inheritance, state (attributes), behavior (methods or actions), encapsulation, message, polymorphism
Usage: building software

12. Record-Based Data Models
Relational data model
Network model
Hierarchical Model

13. Relational Data Model Terminology Record relationship Usage Relations
Attributes
Tuples
Record relationship
One-to-many relationship
Usage
Ad hoc reporting

14. Network Model CODASYL DBTG Terminology Record relationship Usage
Data item & group item
Record type: owner, member
Set type: optional, mandatory, permanent
Record relationship
Many-to-many relationship
Link or pointer between set owner and set member
Usage
Large volume transaction processing

15. Hierarchical Model IBM Information Management Systems Terminology
Tree, general tree, & subtree
Nodes, root node, parent node, and child node
Segment type ( root, parent, child)
Record relationship
One-to-many relationship
Link or pointer between parent node and child node
No many-to-many relationship
Usage
Large volume transaction processing

16. Functions of a DBMS Data storage, retrieval and update
A user-accessible catalog
Transaction support
Concurrency control
Recovery
Authorization
Integrity
Data independence
Data communication
Other Utilities

17. Components of a DBMS Query processor Database manager File manager
DML preprocessor
DDL compiler
Catalog manager

18. Components of Database Manager
Authorization control
Command processor
Integrity checker
Query optimizer
Transaction manager
Scheduler
Recovery manager
Buffer manager

19. Teleprocessing - I Two-tier client-server architecture
Client: user interface, business and data processing logic
Database server: data validation and database access
Advantage
Accessing to distributed database
Increasing performance and consistency
Lowering server and communication cost
Supporting open systems architecture

20. Teleprocessing - II Three-tier client-server architecture
Client: user interface
Application server: business and processing logic
Database server: data validation and database access
Advantage
Reducing client cost
Software distribution
Maintenance cost
Balancing load

21. Teleprocessing - III Transaction processing (TP) monitor
Transaction manager between client and server
Advantage
Transaction routing
Distributed transaction for load balancing