1. Chapter 5
Database Processing

2. 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
GOALS
Illustrate how databases can be used to facilitate decision making.
Show creativity and innovation in processing data to obtain desired results.
Show the value of information when avoiding mistakes.
GearUp managers need data on cancelled customer orders resulting from a supplier canceling a shipment or making a partial shipment. Data will be extracted from multiple, isolated systems and combined and imported to Access so reports can be created.
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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?
This chapter discusses why, what, and how of database processing. It begins by describing purpose of databases and explaining important components of database systems. Next, it gives an overview of creating a database system and your role as a future user.
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4. 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
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5. A List of Student Grades, Presented in a Spreadsheet
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6. Student Data Shown in a Form, from a Database
With a database, a professor can record student grades, s, and office visits all in one place. Forms are difficult, if not impossible, to produce from a spreadsheet, but easily produced with a database.
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Q2: What Is a Database?
A database is a self-describing collection of integrated records.
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8. Components of a Database
Formal term for table is “relation”. Linking relations together creates relationships. A database is a group of related tables. Metadata is a dictionary, of sorts, that describes tables, fields, and relationships.
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9. What Are Relationships Among Rows?
First row of the Table is related to Andrea Baker in Student Table.
Last row in Office_Visit Table related to Adam Verberra in Student Table.
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10. Sample Metadata (in Access)
Access example of metadata for the table. It is metadata that makes a database self-describing.
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11. Ethics Guide: Nobody Said I Shouldn’t
Chris made copy of backup database, took it home
Queried sysTables to find table and field names
Found data on orders, customers, salespeople
Discovered peculiar sales discounts
Mentioned it to Jason (sales clerk)
Chris fired next business day
GOALS
Illustrate the utility of metadata and SQL, even for non-authorized purposes.
Discuss the ethics of unauthorized data access.
Consider the need for organizational data policies.
As a future business manager or owner, what does the ease with which this can be done tell you?
What is a reasonable policy for an organization to have regarding employees taking data home?
Chris most likely uncovered a kickback scheme involving Jason. Jason’s boss might be involved also, which is why Chris was fired.
Chris has two options: (1) He could report what he found to higher-level management, or (2) talk to a lawyer about getting whistleblower protection, or pursuing legal action.
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12. Q3: What Are the Components of a Database Application System?
DBMS is software used to create applications, process data, provide access and manage database. Popular DBMSs: DB2, Microsoft Access, SQL Server, Oracle, MySQL.
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13. Adding a New Column to a Table (in Access)
First DBMS function: Provide a means for creating a database application
Here, developer creates table. User specifies filed names and declares various properties for each field, such as data type, format, caption default value, validation rule, etc. Tables can be easily changed by adding new fields.
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14. Processing the Database
Four DBMS operations
Read
Insert
Modify
Delete
Second DBMS function: Process the database
Such processing can be quite complex. DBMS performs operations to read, insert, modify, or delete data. These operations are requested by applications.
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15. 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);
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16. Summary of Database Administration Tasks
Third DBMS function: Provide tools to assist in database administration
This involves a wide variety of activities. DBMS can be used to set up a security system involving user accounts, passwords, permissions, limits for processing the database, and provide database security.
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17. 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
The Firm’s database contains data on everything customers do. It’s their most important asset.
The Firm’s customers make about 15,000 visits a year, an average of 500 visits per day. It keeps data on every customer and every visit.
Data could be sold to others. It has competitive value because it can be used to improve services and facilities, identify trends, etc.
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18. Q4: How Do Database Applications Make Databases More Useful?
GearUp buyers use first application to schedule events. Operations personnel use Event Setup application to setup the graphics, auction terms and screens. Accounting personnel use Event Accounting application to process event financial results. These applications have different purposes, features, and functions, but they all use Event Database.
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19. What Are Forms, Reports, and Queries?
Example of Student Report
Report structure creates information because it shows student data in meaningful context.
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20. Sample Query Form Used to Enter Phrase for Search and Result
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21. Why Are Database Application Programs Needed?
Process logic specific for a business need
Enable processing via Internet
Four Application Programs on a Web Server Computer
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22. Multi-User Processing Problem
Process A reads customer record from file containing customer’s account balance. 1
Process B reads same record from same file, now has its own copy. 2
Process A updates account balance in its copy of customer record and writes record to file. 3
Process B has original stale value for account balance. Updates customer’s phone number and writes customer record to file. 4
Process B writes stale account balance value to file, causing changes made by Process A to be lost. 5
Lost-update problem is a characteristics of multi-user database processing. To prevent this problem, some type of locking must be used to coordinate the record-update activities of multiple users.
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23. 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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24. Q5: How Are Data Models Used for Database Development?
Database Development Process
Database development process starts with interviewing users to identify database requirements. Requirements are summarized in a data model. Validated data model is transformed into a database design, which is implemented into database structures.
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25. 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), less popular, tool for data modeling
E-R models are a popular tool for constructing data models.
Developers use it to describe content of a data model by defining the things (entities) to be stored in database and relationships among those entities.
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26. Student Data Model Entities
Entities are rectangles. Name of entity above rectangle, and key is shown at the top of the entity. Unlike Student or Adviser, does not have a record key.
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27. Example of Department, Adviser, and Student Entities and Relationships
Diagrams like this one are too cumbersome for use in database design discussions. Instead, database designers use diagrams called entity-relationship (E-R) diagrams.
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Sample E-R Diagrams
Version 1
Crow’s Feet
1:N
N:M
Left side of top figure shows a one-to-many (1:N) relationship between department and advisers. On right is a many-to-many (N:M) relationship between adviser and students. Crow’s feet indicate whether relationship is 1:N or N:M.
Version 2
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29. Crow’s-Foot Diagram Version
Minimum and Maximum Cardinality
Crow’s feet also indicate maximum cardinality with a vertical bar on connecting line. Vertical bar means that at least one entity of that type is required. Symbol for minimum cardinality is a small oval. Oval indicates optional relationship.
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30. Q6: How Is a Data Model Transformed into a Database Design?
Poorly structured Employee table
Database design is process of converting a data model into tables, relationships and data constraints. Database design team transforms entities into tables and expresses relationships by defining foreign keys. Design also involves two important database design concepts: (1) normalization and (2) the representation of two kinds of relationships.
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31. Normalizing for Data Integrity
Two normalized tables
Normalizing tables eliminates data duplication, but can slow processing times. Goal of normalization is to construct tables so every table has a single topic or theme. To do that, a table is split into two tables with each table having a single theme.
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32. Summary of Normalization
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33. Steps for Transforming Data Model Into a Database Design
Construct Adviser table and Student tables with key fields
Represent relationships by adding foreign keys
Create new table for N:M relationships
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34. Transforming a Data Model into a Database Design: 1:N Relationship
Step 1: Represent entities with tables and identifier keys
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35. Representing an N:M Relationship
N:M relationships require creating a new table, Advisor_Student_Intersection.
Step 2: Represent relationships by adding foreign keys
Step 3: Create new tables to represent N:M relationship
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36. 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
Users are final judges of what data the database should contain and how tables should be related.
Users review data models to ensure they accurately reflect users’ views of the business.
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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
With ever cheaper data storage and data communications, databases will become much bigger and more attractive targets for theft or mischief.
Database world will look much different. Use of large non-relational data stores, called NoSQL, on servers in cloud will increase.
Will Microsoft and Oracle and other DBMS vendors lose market to open-source products and become sellers of services supporting open source software like Cassandra?
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38. 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
GOALS
Understand one user’s experience in development of a database application.
Explore security requirements for a shared database.
Understand one way that users respond to technology challenges.
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39. 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.
GOALS
Understand why the statement, “My data model is a better model of reality than your data model” is nonsense—and arrogant!
Realize a data model is a model of users’ mental models, not a model of reality.
Stimulate students’ curiosity about the philosophical foundations of information systems.
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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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41. 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
Goal
Illustrate complexity of Amazon’s Dynamo database server system, Google’s Bigtable and Facebook’s Cassandra.
Stress the competitive importance of a company’s database system.
Illustrate Moore’s Law at work.
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