1. Chapter 4 Database Management Systems

2. Chapter 4Slide 2 What is a Database Management System (DBMS)?  Database An organized collection of related data  Database Management System Comprises programs to store, retrieve, and otherwise manage a computerized database and to provide interfaces to application programs and to non- programming users

3. Chapter 4Slide 3  Storing and Retrieving Data The database sees the physical view of the data  How the data are compressed and formatted, which data are stored near each other, and which indexes are created to simplify and speed finding data on the storage medium Functions of A Database Management System

4. Chapter 4Slide 4  Storing and Retrieving Data The database presents a logical view to the user and programmer  Organizes and presents data elements in ways that managers and other users find helpful Functions of A Database Management System

5. Chapter 4Slide 5  Managing Metadata Metadata are data about data in the database Example  The fact that a company's invoice numbers are six digits long, with the first digit being either a 1 or 3 Functions of A Database Management System

6. Chapter 4Slide 6  Limiting and Controlling Redundant Data in Multiple Systems Companies often collect and store the same data in two or more different information systems Functions of A Database Management System

7. Chapter 4Slide 7  Supporting Simultaneous Data Sharing Concurrency control  Describes the proper management of simultaneous attempts to update a database by multiple users or multiple software programs Functions of A Database Management System

8. Chapter 4Slide 8  Providing Transaction Atomicity The concept that a transaction cannot be split into smaller parts If systems fails in midst of transaction, system is restored as if the entire transaction completed or no part of it completed Functions of A Database Management System

9. Chapter 4Slide 9  Providing Backup and Recovery Services Databases cannot be backed up like files because they are too large and in constant use Backup techniques include  Operating in parallel on two storage devices  Use of temporary database during backup Functions of A Database Management System

10. Chapter 4Slide 10  Providing Authorization and Security Services Most DBMSs can limit who has access to specific data DBMS can create limited views of data so that users can see only what they are authorized to see Functions of A Database Management System

11. Chapter 4Slide 11  Enforcing Business Rules A DBMS enforces rules that ensure related data are logically consistent Functions of A Database Management System

12. Chapter 4Slide 12 Database Applications  Support for Application Software Providing a common data repository Performing support functions, such as data storage, metadata storage, concurrency control, and other DBMS functions that would otherwise have to be performed by the application software

13. Chapter 4Slide 13 Database Applications  Data Warehouse An enterprise-wide database designed to support business intelligence and management decision making rather than operational needs

14. Chapter 4Slide 14  Data Mart Provides summary and historical data for business intelligence and decision making for a single department or division rather than an entire organization Database Applications

15. Chapter 4Slide 15  Serving Dynamic Web Pages Allows Web content managers to change Web pages by updating a database Content management  Software designed to ease the development of Web pages by fields from a database into a Web page template Database Applications

16. Chapter 4Slide 16  Data Design The process of identifying and formalizing the relationships among the elements of data that will form an organization's database Developing Databases through Data Design

17. Chapter 4Slide 17 [Insert Figure 4-4 here] Developing Databases through Data Design

18. Chapter 4Slide 18  Entity-Relationship (E/R) Model The E/R model offers a pictorial way of showing the interrelationships among various types of data Developing Databases through Data Design

19. Chapter 4Slide 19 The Entity- Relationship Model Figure 4-5

20. Chapter 4Slide 20 Technological Underpinnings  Distribution Architecture Refers to how the organization distributes data and database processing physically among the computers in a network

21. Chapter 4Slide 21  Types of Distribution Architectures Decentralized architecture  Involves no data sharing Centralized architecture  Has a single DBMS running on a single computer and maintaining data centrally Technological Underpinnings

22. Chapter 4Slide 22  Types of Distribution Architectures Client/Server architecture  Divides the functions of a DBMS among connected computers on a network, while centralizing permanent storage for all data on a computer called the database server Technological Underpinnings

23. Chapter 4Slide 23  Types of Distribution Architectures Distributed architecture  Distributes both data and processing  Treats data as a single database, giving every database client and every server access to all the data in the database no matter where it resides Mixed architecture  Utilizes more than one architecture Technological Underpinnings

24. Chapter 4Slide 24  Database Models Relational model  A table represents a file with rows called tuples and columns called attributes Technological Underpinnings

25. Chapter 4Slide 25 Technological Underpinnings [Insert Figure 4-8 here]

26. Chapter 4Slide 26  Database Models Object model  Derives from object-oriented programming  Object-oriented DBMSs store objects and object-class metadata Technological Underpinnings

27. Chapter 4Slide 27  Database Models XML model  A language used to mark and identify components of Web-based transaction documents Technological Underpinnings

28. Chapter 4Slide 28  Database Models Network model  Builds a tighter linkage between elements of data Hierarchical model  A precursor to the network model, as a network model with additional restrictions  Views data as organized in a logical hierarchy Technological Underpinnings

29. Chapter 4Slide 29 Managing the Data Resource  Data Administrator Concerned with integrity of data, data redundancy, access controls, and rules about data relationships  Database Administrator (DBA) Oversees functioning of particular DBMS More technical than data administrator

30. End of Chapter 4 End of Chapter 4 Database Management Systems