Chapter 12 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 Figure 12.1 The formulas behind some of the cells

Spreadsheet Formulas Formulas use basic arithmetic operations +, 2, *, and / They also use built-in functions Sum(A2:A3) 12-15

Spreadsheet Formulas Figure 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 Figure 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 fields 12-23

A Database Table Figure 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 Figure 12.8 A database table containing customer data

Relationships We can use a table to represent a collection of relationships between objects 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 Figure 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', ' ') update Movie set Genre = 'thriller drama' where title = 'Unbreakable‘ delete * from Movie where Rating = 'R' 12-32