Transcript Data administration subsystem

CHAPTER 3
DATABASES AND DATA
WAREHOUSES
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 Webbased 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.
2.
3.
4.
5.
DBMS engine
Data definition subsystem
Data manipulation subsystem
Application generation subsystem
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?
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