1 / 57

File Systems and Databases

Chapter 1 The Worlds of Database Systems. File Systems and Databases. Prof. Sin-Min Lee Dept. of Computer Science. Tuesday Thursday 10:15 – 11:30. Your evaluation in this course is determined by:. 30% . Class Presentation 10% Presentation report 5%. ??!. Text Book.

thuy
Download Presentation

File Systems and Databases

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Chapter 1 The Worlds of Database Systems File Systems and Databases Prof. Sin-Min Lee Dept. of Computer Science

  2. Tuesday Thursday 10:15 – 11:30

  3. Your evaluation in this course is determined by: 30% Class Presentation 10% Presentation report 5% ??!

  4. Text Book NARAYAN S. UMANATH & RICHARD W. SCAMELL, DATA MODELING AND DATABASE DESIGN, 2007 Thomson

  5. A. Silberschatz, H.F. Korth, S. Sudarshan: Database System Concepts, 5th Ed., McGraw-Hill, 2006. GOOD REFERENCE

  6. The mediocre teacher tells. The good teacher explains. The superior teacher demonstrates. The great teacher inspires. William Arthur Ward

  7. Files and Databases • File: A collection of records or documents dealing with one organization, person, area or subject (Rowley) • Manual (paper) files • Computer files • Database: A collection of similar records with relationships between the records (Rowley) • Bibliographic, statistical, business data, images, etc.

  8. Introducing the Database • Major Database Concepts • Data and information • Data - Raw facts • Information - Processed data • Data management • Database • Metadata • Database management system (DBMS)

  9. Sales per Employee for Each of ROBCOR’S Two Divisions Figure 1.1

  10. Database Systems • Types of Database Systems • Number of Users • Single-user • Desktop database • Multiuser • Workgroup database • Enterprise database • Scope • Desktop • Workgroup • Enterprise

  11. Database Systems • Types of Database Systems • Location • Centralized • Distributed • Use • Transactional (Production) • Decision support • Data warehouse

  12. Database • A Database is a collection of stored operational data used by the application systems of some particular enterprise (C.J. Date) • Paper “Databases” • Still contain a large portion of the world’s knowledge • File-Based Data Processing Systems • Early batch processing of (primarily) business data • Database Management Systems (DBMS)

  13. Why DBMS? • History • 50’s and 60’s all applications were custom built for particular needs • File based • Many similar/duplicative applications dealing with collections of business data • Early DBMS were extensions of programming languages • 1970 - E.F. Codd and the Relational Model • 1979 - Ashton-Tate and first Microcomputer DBMS

  14. File Based Systems File Application Toys Addresses Delivery List Naughty Coal Estimation Toys Nice Just what asked for

  15. From File Systems to DBMS • Problems with file processing systems • Inconsistent data • Inflexibility • Limited data sharing • Poor enforcement of standards • Excessive program maintenance

  16. DBMS Benefits • Minimal data redundancy • Consistency of data • Integration of data • Sharing of data • Ease of application development • Uniform security, privacy, and integrity controls • Data accessibility and responsiveness • Data independence • Reduced program maintenance

  17. Terms and Concepts • Data independence • Physical representation and location of data and the use of that data are separated • The application doesn’t need to know how or where the database has stored the data, but just how to ask for it • Moving a database from one DBMS to another should not have a material effect on application program • Recoding, adding fields, etc. in the database should not affect applications

  18. CASE Tools User Interface Application Programs Repository DBMS Database Database Environment

  19. DBMS =============== Design tools Table Creation Form Creation Query Creation Report Creation Procedural language compiler (4GL) ============= Run time Form processor Query processor Report Writer Language Run time Database Application Programs Database contains: User’s Data Metadata Indexes Application Metadata User Interface Applications Database Components

  20. Types of Database Systems • PC databases • Centralized database • Client/server databases • Distributed databases • Database models

  21. PC Databases E.g.: Access FoxPro Dbase Etc.

  22. Central Computer Centralized Databases

  23. Client Network Client Database Server Client Client Server Databases

  24. Distributed Databases Location B Location C computer computer Homogeneous Databases computer Location A

  25. Distributed Databases Client Heterogeneous Or Federated Databases Remote Comp. Local Network Database Server Comm Server Remote Comp. Client

  26. Introducing the Database • Importance of DBMS • It helps make data management more efficient and effective. • Its query language allows quick answers to ad hoc queries. • It provides end users better access to more and better-managed data. • It promotes an integrated view of organization’s operations -- “big picture.” • It reduces the probability of inconsistent data.

  27. The DBMS Manages the Interaction Between the End User and the Database Figure 1.2

  28. Introducing the Database • Why Database Design Is Important? • A well-designed database facilitates data management and becomes a valuable information generator. • A poorly designed database is a breeding ground for uncontrolled data redundancies. • A poorly designed database generates errors that lead to bad decisions.

  29. Historical Roots • Why Study File Systems? • It provides historical perspective. • It teaches lessons to avoid pitfalls of data management. • Its simple characteristics facilitate understanding of the design complexity of a database. • It provides useful knowledge for converting a file system to a database system.

  30. Contents of the CUSTOMER File Figure 1.3

  31. Table 1.1 Basic File Terminology

  32. Contents of the AGENT File Figure 1.4

  33. A Simple File System Figure 1.5

More Related