1. Database Development Lifecycle
Database Design
Database Development Lifecycle

2. Database Design: Intro
Database System
Provides data collection, storage, and retrieval
Composed of people, hardware, software, database(s), procedures, and application programs
Database Design
Foundation of a successful database system
Should promote
Data integrity
Prevent data redundancies 반복 & anomalies 오류
Must yield a database that
is efficient in its provision of data access.
meet the objectives of the database system and serves the needs of its users.
Database Design

3. Database Systems: Design, Implementation, & Management: Rob & Coronel
Data Redundancy
Database Systems: Design, Implementation, & Management: Rob & Coronel
Database Design

4. Database Systems: Design, Implementation, & Management: Rob & Coronel
Data Anomaly
Update anomalies 수정오류
- Data inconsistencies resulting from “islands of information” problem
Insertion Anomalies 삽입오류
- Creation of bogus record when adding new data (e.g. new agent)
Deletion Anomalies 삭제오류
- Unintended deletion of related data (e.g. agent data when deleting customer)
Database Systems: Design, Implementation, & Management: Rob & Coronel
Database Design

5. Database Development Database Construction System Construction
System Analysis
Establish the need and extent of an information system
System Development
Design & implement the information system
Database Construction
Planning & Analysis 기획분석
Analyze data environment & Define database objectives
Database Development
Design 설계
Construct a data model & establish data management processes
Implementation 구현
Create the storage structure (e.g., tables) & user interface for data management
Maintenance 정비
(corrective & adaptive) modification, backup & recovery
Database Design

6. Database Development Lifecycle
Planning & Analysis
기획분석
Design
개념 설계
Implementation 구현
Maintenance 정비
 Database Objectives
Business Rules
Data Model
Modification
Backup & Recovery
Security
DBMS Tables
User Interface
SQL Queries
Database Design

7. Database Lifecycle: Planning & Analysis
Database Design
Implement
Maintain
Define Database Objectives
What will the database (DB) do?
What tasks 업무/작업 will the DB support?
Data Entry, Update, Search
What information will the DB provide?
Q & A
Study the DB environment
How does the business operate?
Who are the players?
How does the information flow?
Examine the data
Sample Q&A: Recipe Database
Query
Result
recipe name
recipe info
(ingredients, steps, …)
ingredients
recipe names
 recipe info
main ingredient
(meat, fish, …)
recipe type
(diet, diabetic, …)
recipe category
(soup, desert, …)
budget, time
Database Design

8. Database Lifecycle: Database Design
Planning & Analysis
Database Design
Implement
Maintain
Create a Database Model
that can achieve the database objectives
Conceptual Design – ER Modeling
Logical Design – Relational Schema & Normalization
Physical Design – Schema into DBMS (Table Creation)
What is a Database Model?
Abstract data structure of the real-world items
Need to understand how business works & what role data plays
E-R model verification
E-R model is verified against proposed system processes.
End-user views and required transactions
Access paths, security, concurrency control
Business-imposed data requirements and constraints
Database Design

9. Database Design: Conceptual Design
Planning & Analysis
Database Design
Implement
Maintain
Conceptual Design Steps
Enumerate the Business Rules
How does the business work?
Construct the Data Model
Identify Entities, Relationship & draw an ER Diagram
E-R model verification
E-R model is verified against proposed system processes.
End-user views and required transactions
Access paths, security, concurrency control
Business-imposed data requirements and constraints
Database Design

10. Conceptual Design: Business Rules
Planning & Analysis
Database Design
Implement
Maintain
What
Brief, precise, and unambiguous descriptions of operations in an organization
Based on policies, procedures, or principles within a specific organization
Why
Promote creation of an accurate data model
Enhance understanding & facilitate communication
How (sources)
Interviews, Documentation, Observation
Examples
A painter can draw many paintings. A painting is drawn by a single painter.
A teacher can teach 0 to 6 courses per semester.
A course is taught by a single teacher.
A student must take at least 1 and at most 6 courses.
A course can have 10 to 40 students. 1 M
PAINTER
draws
PAINTING 1 M
TEACHER
teaches
COURSE N
takes M
STUDENT
Database Design

11. Conceptual Design: Data Modeling
Planning & Analysis
Database Design
Implement
Maintain
What is Data Modeling?
A model is a representation of reality that retains only carefully selected essential details.
Logical organization of data for optimum information extraction and data manipulation
Why Model?
To understand and identify essential data elements
How?
Identify Entities 개체, Attributes 속성, & Relationships 관계 ID
STUDENT
GPA
Major
Name
TEACHER
Office
Database Design

12. Database Design: Relational Schema
Planning & Analysis
Database Design
Implement
Maintain
Specification of the overall structure/organization of a database
Relations
Entities w/ Attributes
Primary key
Unique identifier
Foreign key
PK of related table
Relationship type (connectivity)
1:M, M:N, 1:1
Database Design

13. Database Design: Data Dictionary
Planning & Analysis
Database Design
Implement
Maintain
Detailed description of a data model
Lists attribute names and characteristics for each table in the database
Blueprint & documentation of a database
Database Systems: Design, Implementation, & Management: Rob & Coronel
Database Design

14. Database Design: Lifecycle
Define Database Objectives
What information will the database provide?
Examine the Data Environment
How does the business work & what data are used?
Construct the Data Model
Enumerate the Business Rule.
Identify Entities & Relationships between them.
Define Attributes (and primary & foreign keys) for each entity
Create an initial E-R diagram
Normalize the entities 개체 정규화
Process for evaluating & designing good table structures
Verify the Data Model
Does the data model support the database objectives?
If not, modify the Data Model
Database Design

15. Data Model: University Example
Database Design

16. Exercises

17. Data Modeling Exercises
Draw an E-R Diagram of the data model described by the business rules below.
One region can be the location for many stores. Each store is located in only one region.
Each store employs one or more employees. Each employee is employed by one store.
A job can be assigned to many employees. -- e.g., The "Sales Representative" job can be assigned to more than one employee at a time.
Each employee can have only one job assignment.
Draw an E-R Diagram of the data model described by the business rules below.
One region can be the location for many stores. Each store is located in only one region.
Each store employs one or more employees. Each employee is employed by one store.
A job can be assigned to many employees. -- e.g., The "Sales Representative" job can be assigned to more than one employee at a time.
Each employee can have only one job assignment.
Draw an E-R Diagram of the data model described by the business rules below.
One region can be the location for many stores. Each store is located in only one region.
Each store employs one or more employees. Each employee is employed by one store.
A job can be assigned to many employees. -- e.g., The "Sales Representative" job can be assigned to more than one employee at a time.
Each employee can have only one job assignment.
REGION
JOB 1 1
is location for
is assigned to M M 1 M
STORE
employees
EMPLOYEE
Database Design

18. Data Modeling Exercises
Identify the business rules and draw an E-R diagram of the situation described below.
For each professor, there may be multiple advisees. A professor teaches many classes and a class is taught by one professor.
Business Rules
A professor can advise many students.
A student is advised by one professor.
A professor can teach many classes.
A class is taught by one professor 1 M
PROFESSOR
teaches
CLASS 1
advises M
STUDENT
Database Design

19. Data Modeling Exercises
Sample DB
Create a data model (i.e. ERD) for the school database described below.
DB will keep track of advising and class information. DB should provide following information.
- The list of students advised for a given year & dates of advising sessions for each students
- Course listing for each year & student grades for each class
Create a data model (i.e. ERD) for the school database described below.
DB will keep track of advising and class information. DB should provide following information.
- The list of students advised for a given year & dates of advising sessions for each students
- Course listing for each year & student grades for each class
Create a data model (i.e. ERD) for the school database described below.
DB will keep track of advising and class information. DB should provide following information.
- The list of students advised for a given year & dates of advising sessions for each students
- Course listing for each year & student grades for each class
Create a data model (i.e. ERD) for the school database described below.
DB will keep track of advising and class information. DB should provide following information.
- The list of students advised for a given year & dates of advising sessions for each students
- Course listing for each year & student grades for each class
Business Rules
A professor can advise many students. A student is advised by one professor.
A professor can teach many classes. A class is taught by one professor.
A student can take many classes. A class can have many students.
A course can generate many classes. A class is generated by one course.
A professor can meet many times with an advisee. A student can meet many times with the advisor. 1 M
PROFESSOR
teaches
CLASS 1 1 N M 1 M
ADVISING
advises
generates
takes
ENROLL M M M M 1 M 1 1
STUDENT
COURSE
Database Design