Chapter 12

Information Systems

Information Systems

•Spreadsheets•Databases

12-2

Chapter Goals

• Spreadsheets• Spreadsheet “What if” analysis• Spreadsheet formulas• Database Management Systems• Basic SQL statements• Entity-Relationship Diagrams

12-3

Information Systems

• Organization and Storage of Data– database management systems

• Data Analysis– electronic spreadsheets

12-4

Different Tools

• Spreadsheets– Mainly to Analyze Data

• Databases– Mainly to Store Data

• Sometimes, these separate roles overlap

12-5

Lots of Jobs for Specialists

• Database administrator• Database Designer/Programmer• Data Analyst• Information Systems Analyst• Various IT support, supervision, and

management roles• Many, many, many other jobs…

12-6

Lots of Jobs for EVERYBODY

• Most jobs you will find yourself using a database and/or a spreadsheet just to do your job

• Examples:– Doctors and Nurses: Accessing patient medical

records– Grocery Store Clerk: Inventory on store items

12-7

Spreadsheets

12-8

Spreadsheets

• Spreadsheet A software application that allows the user to organize and analyze data using a grid of labeled cells– A cell can contain data or a

formula that is used to calculate a value

– Data stored in a cell can be text, numbers, or “special” data such as dates

– Spreadsheet cells are referenced by their row and column designation

12-9

Common Spreadsheets

• You have your choice of:

• Microsoft Excel– That’s about it…

12-10

Spreadsheets

• Last week at the tutoring center…

12-11

Spreadsheet Analysis

• Spreadsheets can do what-if analysis

– What if the number of attendees decreased by 10%?

– What if we increase the ticket price by $5?

– What if we could reduce the cost of materials by half?

– What if I skipped the midterm exam?

12-12

Spreadsheet Formulas

• The power of spreadsheets comes from formulas– Some cells have input values

– Other cells have formulas that display a calculated value

– Calculated values are AUTOMATICALLY UPDATED when input values change

12-13

Spreadsheet Formulas

12-14Figure 12.1 The formulas behind some of the cells

Spreadsheet Formulas

• Formulas use basic arithmetic operations +, 2, *, and /

• They also use built-in functionsSum(A2:A3)

12-15

Spreadsheet Formulas

12-16Figure 12.4 Some common spreadsheet functions

Spreadsheet Analysis

• Spreadsheets are versatile!• Spreadsheet analysis can be applied to just about any

topic area– Track sales– Analyze sport statistics– Maintain student grades– Keep a car maintenance log– Record and summarize travel expenses– Track project activities and schedules– Plan stock purchases

12-17

Database Systems

12-18

Database Management Systems

• Database A structured set of data• DataBase Management System (DBMS) – Physical database File(s) that contain the data– Database engine Software that accesses the data– Database schema The structure of the data

12-19

Common Databases

• Microsoft Access– Popular PC Database– Good for personal use and for small companies

and organizations• Oracle– Popular powerful DBMS for large organizations

• Microsoft SQL Server– Competition for Oracle

12-20

Database Management Systems

12-21Figure 12.6 The elements of a database management system

Database Management Systems

• The database schema provides the logical view of the data in the database

• The Schema defines:– Tables– Fields names and datatypes– Relationships

12-22

The Relational Model

• In a relational DBMS, the data items and the relationships among them are organized into tables

– A table is a collection of records

– A record is a collection of related fields

– Each field of a database table contains a single data value

– Each record in a table contains the same fields12-23

A Database Table

12-24Figure 12.7 A database table, made up of records and fields

A Database Table

• We can express the schema for this part of the database as follows:

Movie (MovieId:key, Title, Genre, Rating)

12-25

Relationships

12-26

Figure 12.8 A database table containing customer data

Relationships

• We can use a table to represent a collection of relationships between objects

12-27

Figure 12.9 A database table storing current movie rentals

Database Design

• Entity Relationship (ER) Diagram Models the relationships between tables in a graphical form

12-28

An ER Diagram

• A One-to-Many relationship

12-29

Figure 12.10 An ER diagram for the movie rental database

Structured Query Language

• Structured Query Language (SQL) A comprehensive database language for managing relational databases

• SQL allows the user to:– add, modify, delete, and query data

12-30

Queries in SQL

select attribute-list from table-list where condition

select Title from Movie where Rating = 'PG'

select Name, Address from Customer

select * from Movie where Genre like '%action%'

select * from Movie where Rating = 'R' order by Title

12-31

Modifying Database Content

insert into Customer values (9876, 'John Smith', '602 Greenbriar Court', '2938 3212 3402 0299')

update Movie set Genre = 'thriller drama' where title = 'Unbreakable‘

delete * from Movie where Rating = 'R'

12-32