1 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall James A. Senn’s Information Technology, 3 rd Edition Chapter 6 Personal and PC Databases

2 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Objectives Explain why databases are widely used. Describe the main components of a database. List and describe five objectives of database management systems. Identify when a business should use a spreadsheet and when it should use a database.

3 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Objectives (Continued) Identify the seven-step sequence for developing database applications.

4 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall An Overview of Personal and PC Database Systems Definition Database Management System (DBMS): A program that makes it possible for users to manage the data in a database in order to increase accessibility and productivity. Information Repository/Repository: A synonym for database.

5 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall An Overview of Personal and PC Database Systems Reasons for Using Databases Enterprise Database: Large multiuser database systems developed and maintained by IT professionals. Personal Database (PC Database): Typically reside on personal computers and are designed to support a particular function. Storing Data

6 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall An Overview of Personal and PC Database Systems Reasons for Using Databases (Continued) Retrieving Data –Query/Querying: A question to be answered by accessing the data in a database. Editing: Adding, deleting, or changing the data about companies. Organizing Data Distributing Data and Information

7 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall An Overview of Personal and PC Database Systems Special-Purpose Databases General-purpose Database System: A database maintained with powerful database management software that can be applied to just about any PC database. Special-purpose Database: Predesigned for a specific use. Directory: A listing of information by category.

8 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall An Overview of Personal and PC Database Systems Special-Purpose Databases (Continued) Commercial and Government Topical Databases –Economic Database: Capture details related to the state of the U.S. economy (other nations have comparable databases). –Statistical Database: Include the measurement data to measure the level of statistical activity and a means of comparing areas of activity. –Financial Database: Focus on areas of monetary and investment activity, including stock market trading, issuance of mortgages, real-estate transactions, corporate finance, and venture-capital investment activities.

9 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall An Overview of Personal and PC Database Systems Special-Purpose Databases (Continued) Commercial and Government Topical Databases –Literary Database: Pertain to books, monographs, or reports, or to articles appearing in newspapers and magazines. Alternatively, a literary database may contain the actual publications themselves or links to the publications. Personal Information Manager (PIM)/Contact Manager: Contains preprogrammed features enabling users to manage data helpful in their personal activities.

10 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall An Overview of Personal and PC Database Systems Special-Purpose Databases (Continued) Personal Information Manager –Contacts –Calendar –To-Do list –Memos and Notes

11 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall An Overview of Personal and PC Database Systems Database Terminology Entities and Attributes –Entity: A person, place, thing, event, or condition about which data and information are collected. –Attribute: A category of data or information that describes an entity. Each attribute is a fact about the entity. Data Items and Records –Data Item: A specific detail of an individual entity that is stored in a database.

12 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall An Overview of Personal and PC Database Systems Database Terminology (Continued) Data Items and Records –Record: In a database, a designated field used to distinguish one record from another. –Relational Database: A database in which the data are structured in a table format consisting of rows and columns. –Relation/File: The table in a database that describes an entity. –Tuples: The rows of a relation. Also called records. –Fields: The column of a relation. Also called attributes.

13 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall An Overview of Personal and PC Database Systems Database Terminology (Continued)

14 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall An Overview of Personal and PC Database Systems The Objectives of Database Management Systems Data Definition Language (DDL): A tool provided in a database management system that allows users to define the database. Data Manipulation Language (DML): A tool provided in a database management system that allows users to store, retrieve, and edit data in the database.

15 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall An Overview of Personal and PC Database Systems The Objectives of Database Management Systems (Continued)

16 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall An Overview of Personal and PC Database Systems The Objectives of Database Management Systems (Continued) Integrating Databases Reducing Redundancy Sharing Information Maintaining Integrity Enabling Database Evolution

17 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall An Overview of Personal and PC Database Systems Database or Spreadsheet Three Basic Questions –What do I need to do with the data? –How much data do I need to store? –How important are the data?

18 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Developing Database Application Definition Database Application: A computerized database routine for collecting, retrieving, or manipulating data to meet recurring needs.

19 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Developing Database Application Seven Step Sequence Study the Problem: Describe the system’s data entry (input) requirements, inquiry requirements, and output requirements. Determine the Requirements: Determine the problem’s characteristics and how database creating and processing can assist in solving the problems.

20 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Developing Database Application Seven Step Sequence (Continued) Design the Database: Identify entities of interest, determine the data or information that describes them, and determine which data items will be used to distinguish one entity from another. –Index Key/Search Key: A data item used by database management software to locate a specific record. Create the Database: Name the database; establish the database structure (field names, types, widths, and decimal positions; field indexation). –Indexing: A database system’s capability to find fields and records in the database.

21 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Developing Database Application Seven Step Sequence (Continued)

22 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Developing Database Application Seven Step Sequence (Continued) Design the Application: Develop data entry, report generation, and query-processing methods. –Data Entry: The process of populating a database with data and information. Data Entry Form: Custom-developed video display used to enter and change data in a database. –Report Generation –Query Processing Relational Operator: A symbol that tells a database system to make a comparison to call up the requested data.

23 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Developing Database Application Seven Step Sequence (Continued)

24 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Developing Database Application Seven Step Sequence (Continued) Create the Application: Write the programs to perform data-processing tasks. –Custom Programming: In a database system, the writing of detailed procedures, using the commands and functions built into the database management software. –Application Generation: In a database system, the use of menus and simple commands to describe the application to a system program that creates the set of detailed commands.

25 Senn, Information Technology, 3 rd Edition © 2004 Pearson Prentice Hall Developing Database Application Seven Step Sequence (Continued) Test the Application: Evaluate the application’s processes and procedures to ensure they are performing as expected.