1. Evolution of Database System
Database Overview
Evolution of Database System

2. Evolution of Database 1960s 1970s 1980s 1990s 2000+ File-based
Hierarchical
Network
Relational
Object-oriented
Entity-Relationship
Web-based
NoSQL
NewSQL
Database Design

3. Database: Historical Roots
Manual File System
To keep track of data
Used tagged file folders in a filing cabinet
Organized according to expected use
e.g. file per customer
Easy to create, but hard to
locate data
aggregate/summarize data
Computerized File System
To accommodate the data growth and information need
Manual file system structures were duplicated in the computer
Data Processing (DP) specialists wrote customized programs to
write, delete, update data (i.e. management)
extract and present data in various formats (i.e. report)
Database Design

4. Database Systems: Design, Implementation, & Management: Rob & Coronel
File System: Example
Database Systems: Design, Implementation, & Management: Rob & Coronel
Database Design

5. File System: Weakness Weakness Problems Implications
“Islands of data” in scattered file systems 분산된 파일시스템.
Problems
Duplication 중복
Same data may be stored in multiple files
Inconsistency 불일치
Same data may be stored with different values/formats
Rigidity 경직성
Requires customized programming to implement any changes
Cannot do ad-hoc queries 즉석질의 불가
Implications
Waste 낭비 of space
Data inaccuracies 오류
High overhead 간접비용 of data manipulation and maintenance
Database Design

6. File System: Problem Case
CUSTOMER file
AGENT file
SALES file
A_Name (15 char)
A_Name (20 char)
AGENT (20 char)
Carol Johnson
Carol T. Johnson
Carol J. Smith
Inconsistent field name, field size
inconsistent data values
data duplication
Database Design

7. Database System vs. File System
Database Systems: Design, Implementation, & Management: Rob & Coronel
Database Design

8. Hierarchical Data Model 계층적 데이터 모델
Hierarchical Model
To manage large amount of data for complex manufacturing projects
Information Management System developed by Rockwell & IBM
Files connected in Parent-Child (1:M) relationships
1 Parent - Multiple Children
Database Systems: Design, Implementation, & Management: Rob & Coronel
Database Design

9. Hierarchical Data Model 계층적 데이터 모델
Strengths
Conceptual Simplicity 개념적 단순성
Groups of data could be related to each other
Related data could be viewed together
Centralization of data
Reduced redundancy  중복 and promoted consistency  일관성
Weaknesses
Limited representation of data relationships
Did not allow Many-to-Many (M:N) relations
Structural Dependence 구조 의존
Data access requires physical storage path
Complex Implementation 복잡한 구현
Required in-depth knowledge of physical data storage
Lack of Standards 표준 부족
Limited portability
Database Design

10. Network Data Model 네트워크 데이터 모델
Network Model
Extension of Hierarchical Model
Composed of Owner-Member (Parent-Child) sets
To represent Many-to-Many (M:N) relationships
Multiple Parents – Multiple Children
Database Systems: Design, Implementation, & Management: Rob & Coronel
Database Design

11. Relational Data Model 관계형 데이터 모델
Problems with legacy database systems
Required excessive effort to maintain
Data manipulation (programs) too dependent on physical file structure
Hard to manipulate by end-users
No capacity for ad-hoc query (must rely on DB programmers).
Relational Model
E. F. Codd’s proposal
Separated the notion of physical representation (machine-view) from logical representation (human-view)
Eliminated pointers and used tables to represent data
Considered ingenious but computationally impractical in 1970
Dominant database model of today
Separation of design from implementation → Flexible
Ad-hoc queries → Structured Query Language (SQL)
Database Design

12. Relational Database: Example
Tables (i.e. Relations)
Provide a logical “human-level” view of the data and associations among groups of data
Organize data into rows 행 (records/tuples) and columns 열 (attributes)
Are related via shared attribute(s)
Database Design

13. Entity Relationship Model
Peter Chen’s Landmark Paper (1976)
“The Relationship Model: Toward a Unified View of Data”
Graphical representation of entities and their relationships
Based on Entity, Attributes & Relationships
Entity → e.g. EMPLOYEE
Thing about which data are to be collected and stored
Attributes → e.g. SSN, last name, first name
Characteristics of the entity
Relationships → i.e. 1:M, M:N, 1:1
Associations between entities
Complements the relational data model concepts
Helps to visualize structure and content of data groups
Entity Relationship Diagram (ERD) → Tool for conceptual data modeling → Formalizes a way to describe relationships between groups of data
Database Design

14. E-R Diagram: Chen Model
Entity 개체
represented by a rectangle with its name in capital letters.
Relationship 관계
represented by an active or passive verb inside the diamond that connects the related entities.
Connectivity 관계유형
i.e., types of relationship
written next to each entity box.
Database Systems: Design, Implementation, & Management: Rob & Coronel
Database Design

15. E-R Diagram: Crow’s Foot Model
Entity 개체
represented by a rectangle with its name in capital letters.
Relationship 관계
represented by an active or passive verb that connects the related entities.
Connectivity 관계유형
indicated by symbols next to entities.
2 vertical lines for 1
“crow’s foot” for M
Database Systems: Design, Implementation, & Management: Rob & Coronel
Database Design

16. E-R Model: Pros & Cons Advantages Disadvantages
Exceptional conceptual simplicity
Easily viewed and understood representation of database
Facilitates database design and management
Integration with the relational database model
Enables better database design via conceptual modeling
Disadvantages
Incomplete model on its own
Limited representational power
cannot model data constraints not tied to entity relationships
e.g. attribute constraints
cannot represent relationships between attributes within entities
No data manipulation language (e.g. SQL)
Loss of information content
Hard to include attributes in ERD
Database Design

17. Object-Oriented Database 객체지향
Semantic Data Model (SDM)
Modeled both data and their relationships in a single structure (object)
Developed by Hammer & McLeod in 1981
Object-oriented concepts became popular in 1990s
Modularity facilitated program reuse and construction of complex structures
Ability to handle complex data types (e.g. multimedia data)
Object-Oriented Database Model (OODBM)
Maintains the advantages of the ER model but adds more features
Object = entity + relationships (between & within entity)
consists of attributes & methods
methods are all relevant operations that can be performed on an object
Class  Template for objects
e.g. EMPLOYEE class = (employ1 object, employ2 object, …)
organized in a class hierarchy
e.g. PERSON > EMPLOYEE, CUSTOMER
Incorporates the notion of inheritance
attributes and methods of a class are inherited by its descendent classes
Database Design

18. OO Database Model vs. E-R Model
OODBM: - can accommodate relationships within a object - objects to be used as building blocks for autonomous structures
Database Systems: Design, Implementation, & Management: Rob & Coronel
Database Design

19. Object-Oriented Database: Pros & Cons
Advantages
Semantic representation of data
Fuller and more meaningful description of data via object
Modularity, reusability, inheritance
Ability to handle
Complex data
Sophisticated information requirements
Disadvantages
Lack of standards
No standard data access method
Complex navigational data access
Class hierarchy traversal
Steep learning curve
Difficult to design and implement properly
High system overhead
Slow transactions
Database Design

20. Web Database Not a database model, but a system
For storing information that can be accessed via Web
That supports complex data types & relationships
In a Client-Server architecture
Server hosts database & DBMS (e.g., MySQL)
Client accesses the server for database use
Client
Initiates a Connection
Server
Waits & Responds to Incoming Connections
Database
Web Client
(e.g. Chrome)
HTTP request
Web Server
(e.g. Apache)
Data request
DB Server
(e.g. MySQL)
Webpage
Retrieved data
Database Design

21. NoSQL/NewSQL Database
NoSQL (Not Only SQL)
Non-relational: e.g., objects instead tables
For big (unstructured, distributed) data & real-time Web applications
More scalable & better performance
Flexible & agile development
NewSQL
NoSQL + Relational
Consistent
Scalable
Flexible
Database Design

22. MS Access
Introduction
Database Design

23. MS Access: Overview MS Access Theory & Practice
A Database Management System (DBMS)
designed to create applications that organize, store, retrieve, and manipulate large collections of data.
GUI-driven with built-in automations
Based on relational database theory
Theory & Practice
Need a solid understanding of database theory and principles as well as DBMS skills to develop an effective database system.
DBMS expert ≠ Database Design expert

24. MS Access: Database Objects
Tables store data
Forms display data
for viewing, editing, entering
Reports summarize & present data
forms can change data, but reports cannot.
Queries manipulate data
combine, filter, modify, retrieve, etc.
Macros are simplified programs that automate tasks.
Modules are Visual Basic for Application (VBA) programs.
Object Views
(Normal) View
the mode used to interact w/ the object & its data.
Design view
the mode used to change the object design.
GCF LearnFree.org

25. MS Access: User Interface
Database Design
GCF LearnFree.org

26. MS Access: The Ribbon
Minimize
Ribbon
GCF LearnFree.org
Common activities/commands organized by tabs & groups
Tabs → Groups → Commands
Database Design

27. MS Access: Quick Access Toolbar
Right Click
Direct access to any command
Click Customize Quick Access Toolbar icon & select More Commands…
Right-click a command & click Add to Quick Access Toolbar
Database Design

28. MS Access: Navigation Pane
Contains every object in the database
Objects are organized into groups by type
Double-click the object name to open
Right-click to rename
Press the delete key to delete objects
Click the double arrow to minimize/maximize the navigation pane
Database Design

29. MS Access: File Tab Shows general file commands
Recent → Recently open files
Options → Access options
Database Design