1 / 46

File Systems and Databases

Chapter 1. File Systems and Databases. Prof. Sin-Min Lee Dept. of Computer Science. Introducing the Database. Major Database Concepts Data and information Data - Raw facts Information - Processed data Data management Database Metadata Database management system (DBMS).

aine
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 File Systems and Databases Prof. Sin-Min Lee Dept. of Computer Science

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

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

  4. 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.

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

  6. 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.

  7. 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.

  8. Contents of the CUSTOMER File Figure 1.3

  9. Table 1.1 Basic File Terminology

  10. Contents of the AGENT File Figure 1.4

  11. A Simple File System Figure 1.5

  12. File System Critique • File System Data Management • File systems require extensive programming in a third-generation language (3GL). • As the number of files expands, system administration becomes difficult. • Making changes in existing file structures is important and difficult. • Security features to safeguard data are difficult to program and usually omitted. • Difficulty to pool data creates islands of information.

  13. File System Critique • Structural and Data Dependence • Structural Dependence A change in any file’s structure requires the modification of all programs using that file. • Data Dependence A change in any file’s data characteristics requires changes in all data access programs. • Significance of data dependence is the difference between the data logical format and the data physical format. • Data dependence makes file systems extremely cumbersome from a programming and data management point of view.

  14. File System Critique • Field Definitions and Naming Conventions • A good (flexible) record definition anticipates reporting requirements by breaking up fields into their components. • Example: • Customer Name  Last Name, First Name, Initial • Customer Address  Street Address, City, State

  15. File System Critique • Field Definitions and Naming Conventions • Selecting proper field names is very important. • Names must be as descriptive as possible within restrictions. • Naming must reflect designer’s documentation needs and user’s reporting and processing requirements.

  16. File System Critique • Data Redundancy: Uncontrolled data redundancy sets the stage for • Data Inconsistency (lack of data integrity) • Data anomalies • Modification anomalies • Insertion anomalies • Deletion anomalies

  17. Figure 1.6

  18. The Database System Environment Figure 1.7 Figure 1.7

  19. Database Systems • The Database System Components • Hardware • Computer • Peripherals • Software • Operating systems software • DBMS software • Applications programs and utilities software

  20. Database Systems • The Database System Components • People • Systems administrators • Database administrators (DBAs) • Database designers • Systems analysts and programmers • End users • Procedures • Instructions and rules that govern the design and use of the database system • Data • Collection of facts stored in the database

  21. Database Systems • The Database System Components • The complexity of database systems depends on various organizational factors: • Organization’s size • Organization’s function • Organization’s corporate culture • Organizational activities and environment • Database solutions must be cost effective AND strategically effective.

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

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

More Related