The Database Environment
and Development Process
An Overview
1
Outline
 Basic concepts and definitions
 Benefits of Database Management
Systems (DBMS)
 A brief look at the Relational DBMS
 Types of Database Applications
 Database Development Process
2
Figure 1-1b Summarized data
3
Data
4
Basic Concepts and Definitions
 Database
 An organized collection of logically related data
 a list of clients, or customer orders
 organized in a way that enables fast and efficient
storage, access and manipulation
 Data
 Facts that can be recorded and stored using computer
media
 traditionally this included text and numbers
 modern usage now includes objects such as sounds,
images, and video clips
5
Outline
 Basic concepts and definitions
 Benefits of Database Management
Systems (DBMS)
 A brief look at the Relational DBMS
 Database Development Process
6
Traditional File Processing
 Date back to before we had databases
 Still in use today, including backup of database
systems
7
Architecture without DBMS
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Disadvantages of File Processing
 Program-Data Dependence
 All programs maintain metadata for each file they use
 Data Redundancy (Duplication of data)
 Different systems/programs have separate copies of the same
data
 Limited Data Sharing
 No centralized control of data
 Lengthy Development Times
 Programmers must design their own file formats
 Excessive Program Maintenance
 80% of of information systems budget
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Database Management System
Payroll
System
Invoicing
System
Order Filing
System
DBMS
Database
containing
centralized
shared data
DBMS manages data
resources like an operating
system manages hardware
resources
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Solution:
The DATABASE Approach
 Central repository of shared data
 Data is managed by a controlling agent
(DBMS)
 Stored in a standardized, convenient
form
Requires a Database Management System (DBMS)
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Database Management Systems
(DBMS)
 DBMS:
 General-purpose software system which permits data to
be stored non-redundantly and facilitates the processes
of defining, creating, using and maintaining databases
 Database and Repository:
 Includes data and metadata that describes the database
data - the actual values of interest
metadata - descriptions of the characteristics of the
stored data
Data and metadata are stored in one place,
outside of the application program (decoupled from
the code).
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Advantages of Database Approach
 Program-Data Independence
 Metadata stored in DBMS, so applications don’t need to
worry about data formats
 Data queries/updates managed by DBMS so programs
don’t need to process data access routines
 Results in: increased application development and
maintenance productivity
 Minimal Data Redundancy
 Leads to increased data integrity/consistency
13
Advantages of Database Approach
 Improved Data Sharing
 Different users get different views of the data
 Enforcement of Standards
 All data access is done in the same way
 Improved Data Quality
 Constraints, data validation rules
 Better Data Accessibility/ Responsiveness
 Use of standard data query language (SQL)
 Security, Backup/Recovery, Concurrency
 Disaster recovery is easier
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Costs and Risks of the
Database Approach
 Up-front costs:
 Installation Management Cost and Complexity
 Conversion Costs
 Ongoing Costs
 Requires New, Specialized Personnel
 Need for Explicit Backup and Recovery
 Organizational Conflict
 Old habits die hard
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Evolution of DB Systems
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Outline
 Basic concepts and definitions
 Benefits of Database Management
Systems (DBMS)
 A brief look at the Relational DBMS
 Database Development Process
17
Relational Databases Organize
Data in Tables
Field 1
Field 2
Field 3
Record 1
Record 2
Record 3
column represents a Field (a.k.a attribute,
characteristic)
• Each
•Each row represents a Record (a.k.a instance, tuple)
•Database typically includes a set of tables
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Example: data in relational form
Name
ID
Major
GPA
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Practice problem
Design a database to record information about students
and their advisors. The following rules apply.
Each student is assigned a unique ID and a single
advisor. Database needs to keep track of students and
advisors in a given semester.
The database should allow the student to look up their
advisor’s name and email.
The same database should allow the advisors to find
out if they have advisees, who their advisees are and
what their major is.
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Use this space for your solution
21
May seem simple, but…
Example: poorly designed database.
The purpose of this table is to keep track of students, their majors per semester,
advisors and their email addresses.
Semester ST_ID ST_FIRST ST_LAST ST_MAJOR
ADV_FIRST ADV_LAST ADV_EMAIL ADV_ID
F-09
001
Adam
Gopnik
Literature
William
Shakespeare
ws@lu.ac.uk
352
F-09
035
Sandra
Smith
Literature
James
Joyce
jj@dbl.edu
465
S-10
735
Barbara
Richards
Astronomy
Galileo
Galilei
gg@pdv.it
773
S-10
136
Preston
Jones
Astronomy
Galileo
Galilei
gg@pdv.it
773
S-10
035
Sandra
Smith
Math
Carl
Gauss
kg@lu.ac.de
554
Consider what would happen when the table has to be updated to reflect the following
events:
1.Sandra Smith graduates.
2.Galilei’s email has changed
3.A new professor is hired and has to be assigned an ID that must be recorded,
but has not yet been assigned any students to advise.
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The Database Design Process
 Enterprise modeling
 Specifies scope and general content
 Conceptual modeling
 Entity-Relationship Diagrams (ERDs)
 Logical Design
 Translate the conceptual model into files, tables,
or objects (depending on type of DBMS)
 Physical Design
 Lay out the actual DBMS architecture
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Figure 1-3 Conceptual data model (ERD)
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Figure 1-4 Order, Order_Line, Customer, and Product tables
Relationships established in special columns (or tables) that
provide links between tables representing the entities.
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Data Tables (Relations)
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Relationships
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The Range of
Database Applications
 Personal Database – standalone desktop
database
 Workgroup Database – local area network
(<25 users)
 Department Database – local area network
(25-100 users)
 Enterprise Database – wide-area network
(hundreds or thousands of users)
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Outline
 Basic concepts and definitions
 Benefits of Database Management
Systems (DBMS)
 A brief look at the Relational DBMS
 Database Development Process
29
Human Resources Needed
 Systems Analysts
 Database Analysts/Designers
 Data/Database Administrators
 Programmers
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Enterprise Data Model
 A model which includes:
 overall range of organizational databases
 general contents of organizational databases
 Built as part of IS planning for the
organization and not the design of a
particular database
 One part of an organization’s overall
information systems architecture (ISA)
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Data Entity
Types
Business
Function (users)
Business Planning
Product Development
Materials Management
Order Fulfillment
Order Shipment
Sales Summarization
Production Operations
Finance and Accounting
Customer
Product
Raw Material
Order
Work Center
Work Order
Invoice
Equipment
Employee
Example business function-to-data
entity matrix (fig. 2.3)
X
X
X
X
X X
X X
X X
X
X X
X X
X
X
X
X X X X
X
X X X X X X X
X X
X
X
X
X
X
X X X X
X X
X X X
X X X 32
Conceptual Database Modeling
 Determine user requirements
 Determine business rules
 Build conceptual data model
 outcome is an entity-relationship
diagram or similar communication
tool
Enterprise
Modeling
Conceptual
Data Modeling
Logical
DB Design
Physical DB
Design/Creation
DB
Implementation
DB
Maintenance
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Logical Database Design
 Select logical database model
 Map Entity-Relationship Diagrams
 Normalize data structures
 Specify business rules
Enterprise
Modeling
Conceptual
Data Modeling
Logical
DB Design
Physical DB
Design/Creation
DB
Implementation
DB
Maintenance
34
Physical Database Design
 Select DBMS
 Select storage devices
 Determine access methods
 Design files and indexes
 Determine database distribution
 Specify update strategies
Enterprise
Modeling
Conceptual
Data Modeling
Logical
DB Design
Physical DB
Design/Creation
DB
Implementation
DB
Maintenance
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