CHAPTER 3

DATABASES AND DATA WAREHOUSES

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OPENING CASE STUDY

• Chrysler Spins a Competitive Advantage with Supply Chain Management Software

• Chapter 2 – supply chain management is a key business initiative

• Chrysler’s SCM is called SPIN, a Web-based system

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OPENING CASE STUDY

• Behind SPIN are powerful databases• Databases store a wealth of information

– Inventory– Work-in-progress– Supplier information– Recall notices– Customer purchases

• This chapter – databases and data warehouses

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INTRODUCTION

• Organizations need business intelligence

• Business intelligence (BI) – knowledge about your customers, competitors, business partners, competitive environment, and internal operations to make effective, important, and strategic business decisions

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INTRODUCTION

• IT tools help process information to create business intelligence according to:– OLTP– OLAP

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INTRODUCTION

• Online transaction processing (OLTP) – the gathering of input information, processing that information, and updating existing information to reflect the gathered and processed information– Databases support OLTP– Operational database – databases that

support OLTP

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INTRODUCTION

• Online analytical processing (OLAP) – the manipulation of information to support decision making– Databases can support some OLAP– Data warehouses only support OLAP, not

OLTP– Data warehouses are special forms of

databases that support decision making

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INTRODUCTION

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THE RELATIONAL DATABASE MODEL

• There are many types of databases

• The relational database model is the most popular

• Relational database – uses a series of logically related two-dimensional tables or files to store information in the form of a database

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Databases Are…

• Collections of information

• Created with logical structures

• With logical ties within the information

• With built-in integrity constraints

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Databases – Collections of Information

• Databases have many tables

• Consider Solomon Enterprises that provides concrete to home and commercial builders. Tables or files include:– Order– Customer– Concrete Type– Employee– Truck

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Databases – Collections of Information

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Databases – Created with Logical Structures

• In databases, the row number is irrelevant

• Not true in spreadsheet software

• In databases, column names are very important. Column names are created in the data dictionary

• Data dictionary – contains the logical structure of the information in a database

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Databases – With Logical Ties Within the Information

• Logical ties must exist between the tables or files in a database

• Logical ties are created with primary and foreign keys

• Primary key – field (or group of fields in some cases) that uniquely describes each record

• Can you find primary keys in Figure 3.1 on page 129?

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Databases – With Logical Ties Within the Information

• Foreign key – primary key of one file that appears in another file

• Foreign keys help you create logical ties within the information in a database

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Databases – With Logical Ties Within the Information

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Databases – With Built-In Integrity Constraints

• Integrity constraints – rules that help ensure the quality of the information

• Examples– Primary keys must be unique– Foreign keys must be present– Sales price cannot be negative– Phone number must have area code

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DATABASE MANAGEMENT SYSTEM TOOLS

• Database management system (DBMS) – helps you specify the logical organization for a databases and access and use the information within a database– Word processing software = document– Spreadsheet software = workbook– DBMS software = database

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DATABASE MANAGEMENT SYSTEM TOOLS

• 5 software components:1. DBMS engine

2. Data definition subsystem

3. Data manipulation subsystem

4. Application generation subsystem

5. Data administration subsystem

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DATABASE MANAGEMENT SYSTEM TOOLS

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DBMS Engine

• DBMS engine – accepts logical requests from the various other DBMS subsystems, converts them into their physical equivalent, and actually accesses the database and data dictionary as they exist on a storage device

• DBMS engine separates the logical from the physical

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DBMS Engine

• Physical view – how information is physically arranged, stored, and accessed on some type of storage device

• Logical view – how you as a knowledge worker need to arrange and access information

• With a database, you only concern yourself with your logical view

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Data Definition Subsystem

• Data definition subsystem – helps you create and maintain the data dictionary and define the structure of the files in a database

• You must create a data dictionary before entering information into a database

• Module J covers this for Microsoft Access

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Data Manipulation Subsystem

• Data manipulation subsystem – helps you add, change, and delete information

• This is your primary DBMS interface as you work with a database– Views– Report generators– QBE tools– SQL

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Views

• View – allows you to see the contents of a database file– Make whatever changes you want– Perform simple sorting– Query to find the location of information– Looks similar to a workbook with no row

numbers

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Views

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Report Generators

• Report generator – helps you quickly define formats of reports and what information you want to see in a report

• You can save report formats and generate reports at any time with up-to-date information

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Report Generators

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Report Generators

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QBE Tools

• Query-by-example (QBE) tool – helps you graphically design the answer to a question

• “What driver most often delivers concrete to Triple A Homes?”

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QBE Tools

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SQL

• Structured query language (SQL) – standardized fourth-generation language found in most DBMSs

• Performs the same task as a QBE tool– But uses a sentence structure instead of

point-and-click interface

• SQL is used mostly by IT people

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Application Generation Subsystem

• Application generation subsystem – contains facilities to help you develop transaction-intensive applications– Data entry screen (called forms)– Programming languages

• Used mostly by IT specialists

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Data Administration Subsystem

• Data administration subsystem – helps you manage the overall database environment– Backup and recovery– Security management– Query optimization– Concurrency control– Change management

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Data Administration Subsystem

• Backup and recovery– Periodically back up information– Recover a database if a failure occurs

• Security management– Who has access to what information– Who can perform certain tasks (e.g., add,

change, or delete) on information

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Data Administration Subsystem

• Query optimization– Restructure physical view of information to

optimize response times to queries

• Concurrency control– What happens if two people makes changes

to the same information at the same time?

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Data Administration Subsystem

• Change management– What is the effect of structural changes to a

database?– What if you add a new column?– What happens if you delete a column?– What happens if you change a column’s

attributes?