5장

Database Processing

• Dee selected Movable Type application program

• Needs database program to store blog

– Consultant suggested MySQL

– Network standardized on Oracle

• May not be able to run Movable Type

• Will require revision of labor estimates

– IT resists installing MySQL

5-2

This Could Happen to You

• To organize and keep track of things

• Spreadsheets do that too – Keep lists of single concept

– Example: Student test scores in a course

• Databases – Keep lists that involve multiple themes/concepts

– Examples: Student grades, grades for all courses in a department, courses offered in all departments, faculty records, and so on

Q1: What Is the Purpose of a

Database?

5-3

• Self-describing collection of integrated records

• Hierarchy of data elements – Bytes/data are grouped into columns/fields

– Columns grouped into rows/records

– Rows are grouped into tables/files

• Collection of tables plus relationships among rows – Also includes “metadata”

• Describes the structure of the database

• A database is a structured collection of records or data that is stored in a computer system so that a computer program or person using a query language can consult it to answer queries.

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Q2: What Does a Database Contain?

Student Table (also called a file)

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• Values in one table may relate to rows/records in

other tables

• Keys

– Column(s) that identify unique row in table

– Each table has a key

• Foreign keys

– Keys of a different table than the one in which they reside

• Relational databases

– Databases using tables, keys, and foreign keys

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Relationships Among Records

5-7

Example of Relationships

Among Rows

Figure 5-6

• Database is self-describing

– Contains descriptions of its data

• Metadata – Data that describe data – Make databases more useful – Make databases easier to use

• Describe data

– Data type – Field name – Field properties

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Metadata

• Database management system (DBMS)

–Program that creates, processes, and administers database

–Usually licensed from vendors

–Examples: Microsoft Access, Oracle, MySQL, DB2

• DBMS and database are two different things

–Database is a structured collection of records or data that is stored in a computer system so that a computer program or person using a query language can consult it to answer queries. The computer program used to manage and query a database is known as a database management system (DBMS).

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Q3: What Is a DBMS and

What Does It Do?

Components of a Database

Application System

5-10

• DBMS used to create tables, relationships in

databases

• Applications use DBMS to read, insert,

modify, and delete data

– Structured Query Language (SQL) • International standard for processing database

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Database Management Systems

Creating the Database and Its Structure

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• Four DBMS operations 1. Read data

2. Insert data

3. Modify data

4. Delete data

• Structured Query Language INSERT INTO Student

([Student Number], [Student Name], HW1, HW2,

MidTerm)

VALUES

(1000, ‘Franklin, Benjamin’, 90, 95, 100)

Processing the Database

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• DBMS security features used to set up user

accounts, passwords, permissions,

processing limits

– Permissions – data access rights for specific users

or groups of users

• Database backup and replication, adding

structures, removing unneeded data

Administering the Database

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• Collection of forms, reports, queries, and

application programs that process a database

• Databases can have multiple applications

• Applications can have multiple users

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Q4: What Is a Database Application?

Use of Multiple Database Applications

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• Forms – Used to read, insert, modify, and delete data

• Reports – Show data in structured context

– May compute values

• Queries – Are a means of getting answers from database

data

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Forms, Reports, and Queries

• Application programs

– Process logic specific to a business need

– May enable database processing over Internet to:

• Serve as intermediary between Web server and database

• Respond to events

• Read, insert, modify, delete data

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Database Application Programs

Example of a Query

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• Enterprise DBMS – Processes large organizational and workgroup

databases – Supports many users (thousands plus) – Examples: DB2, SQL Server, Oracle, DB2

• Personal DBMS

– Designed for smaller, simpler database applications

– Supports fewer than 100 users – Examples: Access, dBase, FoxPro, Paradox, R-

Base

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Q5: What Is the Difference Between an

Enterprise DBMS and a Personal DBMS?

Personal Database System

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Helps to:

• Know what a DBMS is and what roles it can play

• Understand the diagram of the role of the DBMS for

her blog

– System is isolated from rest of databases

– Uses MySQL as part of functionality of her application

• Be better able to explain what she wants, and that it is

no threat or exception to Oracle standard

• Maybe avoid hiring a consultant

5-22 Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

How Does the Knowledge in This

Chapter Help Dee and You?

5-23 Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

Role of DBMS for Dee’s Blog

• Databases take time to build

• Complicated to operate

– May require use of multiple applications

• Need IS people to create it and keep it

running

• Will share data that you may not want to

expose

• Spreadsheets may be a better option in some

cases

5-24

Guide: No, Thanks, I’ll Use a

Spreadsheet