Transcript The Database Environment - Eastern Michigan University
Agenda
01/13/05
•
Announcement
•
Database Development Process (Chapter 2)
1
Announcement
•
A Quiz about Chapter 9
– –
Open book on Tuesday, 01/18/05 Bring your database textbook (or a copy of chapter 9) to the class
•
For your diagramming software, visit the following web site and download a RFlow trial version: http://graphicssoft.about.com/cs/diagramswpc
2
Database Development Process
(Chapter 2)
3
“It is a capital mistake to theorize before one has data”
Sherlock Holms’ remarks in A Scandal in Bohemia (Sir Conan Doyle, 1891)
4
4.
5.
6.
7.
8.
1.
2.
3.
8 Underlying Principles of Systems Development Get the Users Involved Use a Problem-Solving Approach Establish Phases and Activities Establish Standards for Consistent Development and Documentation Justify Systems as Capital Investments Don’t Be Afraid to Cancel or Revise Scope Divide and Conquer Design Systems for Growth and Change
5
Strategies for IS Development
Top-Down
Proceeds from general to specific Particular systems are designed working from a broad knowledge of the entire organizations information needs
Bottom-Up Proceeds from specific to general Individual systems are designed from a detailed knowledge of a distinct application
6
Information Systems Development Process Sources
Information systems planning (top-down)
User application requests (bottom-up) IS Development Approaches
Systems Development Life Cycle (SDLC)
Rapid Application Development (RAD) - Prototyping
7
Information Systems Planning Process Organization Mission Business Assessment Organization Strategic Plan Current IT Architecture IS Strategic Plan New IT Architecture IS Operational Plan IS Development Projects (i.e. Database Development)
8
Systems Development Life Cycle (SDLC) 1.
2.
3.
4.
System Identification and Selection Project Initiation and Planning Analysis Logical Design 5. Physical Design 6. Implementation 7. Maintenance
9
• • • • • •
System Identification and Selection Problem determination Understanding of the business situation Feasibility study Justification for the system Authorization to proceed Priority
10
Project Initiation and Planning
• • • • •
Scope of the project Project schedule Resource requirements Systems architecture Enterprise data model
11
Analysis
System requirements (detailed) Conceptual model
12
Logical Design
Functional specification of system components (detailed)
13
Physical Design
Technical specification of system components (detailed)
14
Implementation
• • •
System installation Applications Documentation Training
15
Maintenance
•
System Monitoring
•
Repairing
•
Upgrade
•
Support
16
Project Planning Analysis
Requirements E-R Data Model
Logical Design
Relational database Model Qulaity Control Checks
Physical Design
Technical Specifications Define the database to the DBMS
Implementation
Data Entry Information Retrieval (SQL)
Database SDLC Maintenance
17
Database Development Activities in the SDLC 1.
2.
3.
4.
5.
6.
Planning Analysis Logical Design Physical Design Implementation Maintenance
18
•
Planning
Examine the information systems architecture (blue print) Review the enterprise data model Establish the general scope of the database
19
Analysis
•
Determine the specific data requirements for the system
•
Create the conceptual data model: Entity-Relationship Diagram (ERD)
20
Basic Entity-Relationship Example
ACCOUNT Has EXPENSE
21
Prof-ID Prof-Name
PROFESSOR E-R Diagram Example
Is Qualified
COURSE
(4) Course-Num Course-Title Is Scheduled Semester 22
Logical Design
•
Convert the data model to a database design: Relational Schema
•
Perform quality control tuning on the logical database design - Integrity constraints - Normalized relations
23
E-R Diagram
ACCOUNT HAS EXPENSE
Relations (plus Relational SCHEMA)
ACCOUNT (ACCOUNT_NO, ……) EXPENSE (EXPENSE_CODE, ACCOUNT_NO) Plus Constraints, Integrity Rules, Domain……….
24
Physical Design
Stipulate technical data specifications
Define the database design to the DBMS
•
Construct data entry mechanisms
25
Implementation
Load the data
Build the applications
•
Produce documentation
26
Maintenance
Tune the database for performance
Provide security and recovery
•
Support the software and files
27
Schema
•
The conceptual organization of the entire database as viewed by stakeholders
•
The structure that contains descriptions of objects created by a user such as tables, views and constraints
28
Three Schema Architecture for Database Development Conceptual Schema
Analysis phase: E-R Diagram
Logical Design phase: Relational (Logical) Schema Internal Schema
Physical Design phase: DBMS Definition External Schema
Implementation phase: User Views
29
External Schema
Reports (user View) Forms (User view) Programs (User View)
Conceptual Schema Internal Schema T hree Schema Database Architecture
30
Components of Application Logic Involving Data Input / Output
Manage user input from the keyboard
Format and present output (screens and hardcopy)
Processing
Data validation
Business rules Data update Data and information retrieval Storage
Performance
Security
31
People in Database Development Systems analysts Programmers Database analysts Database and data administrators Systems programmers & network administrators Technical writers Users
32
To Download RFFLOW Software Go to http://graphicssoft.about.com/cs/diagramswpc
33