Using MIS 6e Chapter 5

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Transcript Using MIS 6e Chapter 5

Chapter 5 Database Processing

GearUp: “YOU Don’t Know Anything About Report Writing” • GearUp needs operating data to analyze for cost-cutting decisions • Need to extract and combine data from multiple systems • Will use Access to create reports Copyright © 2014 Pearson Education, Inc. Publishing as Prentice Hall 5-2

Study Questions Q1: What is the purpose of a database?

Q2: What is a database?

Q3: What are the components of a database application system?

Q4: How do database applications make databases more useful?

Q5: How are data models used for database development?

Q6: How is a data model transformed into a database design?

Q7: What is the users’ role in the development of databases?

Q8: 2023?

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Q1: What Is the Purpose of a Database?

• Organize and keep track of things • Keep track of multiple themes • General rule:  Single theme store in a spreadsheet  Multiple themes require a database Copyright © 2014 Pearson Education, Inc. Publishing as Prentice Hall 5-4

A List of Student Grades, Presented in a Spreadsheet Copyright © 2014 Pearson Education, Inc. Publishing as Prentice Hall 5-5

Student Data Shown in a Form, from a Database Copyright © 2014 Pearson Education, Inc. Publishing as Prentice Hall 5-6

Q2: What Is a Database? Copyright © 2014 Pearson Education, Inc. Publishing as Prentice Hall 5-7

Components of a Database Copyright © 2014 Pearson Education, Inc. Publishing as Prentice Hall 5-8

What Are Relationships Among Rows?

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Sample Metadata

(in Access)

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Ethics Guide: Nobody Said I Shouldn’t 1. Chris made copy of backup database, took it home 2. Queried sysTables to find table and field names 3. Found data on orders, customers, salespeople 4. Discovered peculiar sales discounts 5. Mentioned it to Jason (sales clerk) 6. Chris fired next business day Copyright © 2014 Pearson Education, Inc. Publishing as Prentice Hall 5-11

Q3: What Are the Components of a Database Application System?

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Adding a New Column to a Table (in Access) Copyright © 2014 Pearson Education, Inc. Publishing as Prentice Hall 5-13

Processing the Database Four DBMS operations 1. Read 2. Insert 3. Modify 4. Delete Copyright © 2014 Pearson Education, Inc. Publishing as Prentice Hall 5-14

Structured Query Language (SQL) •

SQL (

see-quell) – International standard – Used by most popular DBMS • SQL statement: – INSERT INTO Student  ([Student Number], [Student Name], HW1, HW2, MidTerm) – VALUES  (1000, ’Franklin, Benjamin’, 90, 95, 100); Copyright © 2014 Pearson Education, Inc. Publishing as Prentice Hall 5-15

Summary of Database Administration Tasks Copyright © 2014 Pearson Education, Inc. Publishing as Prentice Hall 5-16

Using MIS InClass 5: How Much Is a Database Worth?

• Data has resale value • Data on everything customers do • Use to target customer for offerings they care about, avoid those they don’t • Costly and difficult to replace data collected over many years Copyright © 2014 Pearson Education, Inc. Publishing as Prentice Hall 5-17

Q4: How Do Database Applications Make Databases More Useful? Copyright © 2014 Pearson Education, Inc. Publishing as Prentice Hall 5-18

What Are Forms, Reports, and Queries?

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Sample Query Form Used to Enter Phrase for Search and Result Copyright © 2014 Pearson Education, Inc. Publishing as Prentice Hall 5-20

Why Are Database Application Programs Needed?

• Process logic specific for a business need • Enable processing via Internet Copyright © 2014 Pearson Education, Inc. Publishing as Prentice Hall 5-21

Multi-User Processing Problem 1. Process A reads customer record from file containing customer’s account balance. 3. Process A updates account balance in its copy of customer record and writes record to file. 5. Process B writes stale account balance value to file, causing changes made by Process A to be lost. 1 2 2. Process B reads same record from same file, now has its own copy. 3 4 5 4. Process B has original number and writes

stale

value for account balance. Updates customer’s phone customer record to file. Copyright © 2014 Pearson Education, Inc. Publishing as Prentice Hall 5-22

Enterprise DBMS vs. Personal DBMS • Enterprise DBMS process large organizational and workgroup databases for 100s/1000s of users • Personal DBMS designed for smaller databases used by 1 to 100 users.

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Q5: How Are Data Models Used for Database Development?

Database Development Process Copyright © 2014 Pearson Education, Inc. Publishing as Prentice Hall 5-24

What Is the Entity-Relationship (E-R) Data Model?

• • Tool for constructing data models • Describes contents of data model by defining entities and relationships among entities Unified Modeling Language (UML) popular, tool for data modeling , less Copyright © 2014 Pearson Education, Inc. Publishing as Prentice Hall 5-25

Student Data Model Entities Copyright © 2014 Pearson Education, Inc. Publishing as Prentice Hall 5-26

Example of Department, Adviser, and Student Entities and Relationships Copyright © 2014 Pearson Education, Inc. Publishing as Prentice Hall 5-27

Sample E-R Diagrams Version 1 Crow’s Feet 1:N N:M Version 2 Copyright © 2014 Pearson Education, Inc. Publishing as Prentice Hall 5-28

Crow’s-Foot Diagram Version Minimum and Maximum Cardinality Copyright © 2014 Pearson Education, Inc. Publishing as Prentice Hall 5-29

Q6: How Is a Data Model Transformed into a Database Design?

Poorly structured Employee table

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Normalizing for Data Integrity

Two normalized tables

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Summary of Normalization Copyright © 2014 Pearson Education, Inc. Publishing as Prentice Hall 5-32

Steps for Transforming Data Model Into a Database Design 1. Construct Adviser table and Student tables with key fields 2. Represent relationships by adding foreign keys 3. Create new table for N:M relationships Copyright © 2014 Pearson Education, Inc. Publishing as Prentice Hall 5-33

Transforming a Data Model into a Database Design: 1:N Relationship Copyright © 2014 Pearson Education, Inc. Publishing as Prentice Hall 5-34

Representing an N:M Relationship Copyright © 2014 Pearson Education, Inc. Publishing as Prentice Hall 5-35

Q7: What Is the Users’ Role in the Development of Databases?

• Define what data database must contain • User review of data model is crucial – Does model accurately reflect your view of the business ? • Final approval of data models • Devote time to do it right Copyright © 2014 Pearson Education, Inc. Publishing as Prentice Hall 5-36

Q8: 2023? • Volume of database data to grow exponentially • Relational databases will look much different • Use of non-relational data stores, called NoSQL will be more common • Major DBMS vendors lose out to open-source products and shift focus to services supporting open source software like Bigtable, Dynamo, Cassandra?

• Database models will be very different Copyright © 2014 Pearson Education, Inc. Publishing as Prentice Hall 5-37

Guide: No, Thanks, I’ll Use a Spreadsheet • Databases take time to build • Complicated to operate • Need IS people to create and keep them running • Salesman doesn’t want to share data • Spreadsheets sometimes better option, especially if data needs are simple Copyright © 2014 Pearson Education, Inc. Publishing as Prentice Hall 5-38

Guide: Immanuel Kant, Data Modeler • Perception of reality is based on our perceptive apparatus.

• Brain processes perceptions into something meaningful.

• Human’s model what appears to be. • Users must determine if a data model fits their perception of reality.

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Active Review Q1: What is the purpose of a database?

Q2: What is a database?

Q3: What are the components of a database application system?

Q4: How do database applications make databases more useful?

Q5: How are data models used for database development?

Q6: How is a data model transformed into a database design?

Q7: What is the users’ role in the development of databases?

Q8: 2023?

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Case Study 5: Fail Away with Dynamo, Bigtable, and Cassandra • Current relational DBMS products not designed for large, multi-server systems • NoSQL databases

Dynamo, Bigtable, Cassandra • Amazon: Dynamo • Google: Bigtable processes petabytes of data on hundreds of thousands of servers • Both created to be elastic • Cassandra used by Facebook, Twitter, Digg, Reddit Copyright © 2014 Pearson Education, Inc. Publishing as Prentice Hall 5-41

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