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Database Management Systems

Chapter 4. Database Management Systems. What is a Database Management System (DBMS)?. Database An organized collection of related data Database Management System

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Database Management Systems

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  1. Chapter 4 Database Management Systems

  2. What is a DatabaseManagement 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 Chapter 4

  3. Functions of A Database Management System • 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 Chapter 4

  4. Functions of A Database Management System Functions of A Database Management System • 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 Chapter 4

  5. Functions of A Database Management System Functions of A Database Management System • 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 Chapter 4

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

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

  8. Functions of A Database Management System Functions of A Database Management System • 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 Chapter 4

  9. Functions of A Database Management System Functions of A Database Management System • 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 Chapter 4

  10. Functions of A Database Management System • 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 Chapter 4

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

  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 Chapter 4

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

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

  15. Database Applications • 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 Chapter 4

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

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

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

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

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

  21. Technological Underpinnings • 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 Chapter 4

  22. Technological Underpinnings • 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 computercalled the database server Chapter 4

  23. Technological Underpinnings • 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 Chapter 4

  24. Technological Underpinnings • Database Models • Relational model • A tablerepresents a file with rows called tuplesand columns called attributes Chapter 4

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

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

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

  28. Technological Underpinnings • 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 Chapter 4

  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 Chapter 4

  30. End of Chapter 4 Database Management Systems

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