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1960’s

A pioneer in the field was Charles Bachman

Network Model: 1st DBMS Integrated Data Store
Standardized by CODASYL .. Conference On Data Systems Languages

Hierarchical Model: IBM’s IMS:
Information Management System is still used!
1970’s

E. F. Codd introduced Relational Model (1971)

Chen developed ER model (1976)

Relational DB’s appeared in late 70’s
1980’s

Relational DBMS’s dominate

Preliminary SQL standard published (query language)

Object-oriented concepts emerge

distributed DBMS‟s become an important area of research
1990’s

Client-server takes over

legacy DBs become a major problem

new areas such as data warehousing, multimedia emerge
2000

Databases survive Y2K!

Databases are still based on relational model!

Databases become web-accessible

DBMSs become embedded components in application systems (such as
electronic commerce applications).
Database Systems Lecture Notes
1. What is a database?
A collection of related data. ‘Data’ mean known facts that can be recorded and
that have implicit meaning. Example names, telephone numbers and addresses of the
person.
2. Database properties:
a. It represents some aspect of the real world (miniworld). Changes to the
miniworld reflected in the database.
b. It is a logically coherent collection of data with some inherent meaning.
c. A database is designed, built, and populated with data for a specific purpose.
.
A database can be of any size and of varying complexity
3. What is a database management system (DBMS)?
Software that manages and controls access to a DB. It is a collection of programs
that enables user to create and maintain a database. The DBMS is hence a generalpurpose software system the facilitates the process of defining, constructing and
manipulating databases for various applications.
a. Defining: specifying the data types, structures and constraints for the data to
be stored in the database.
b. Constructing: process of storing the data in some storage medium that is
controlled by the DBMS.
c. Manipulating: includes functions such as querying the database to retrieve
specific data, updating the database to reflect changes in the miniworld and
generating reports from the data.
Examples: Oracle, DB2 (IBM), MS SQL Server, MS Access, Ingres (RDBMS),
PostgreSQL, MySQL
Database System = database + DBMS software
Database
System
Environment
Users/Programs
Database System
Application Programs/Queries
DBMS Software
Software to Process
Queries/Programs
Software to Access Stored data
Stored Database
Definition (MetaData)
Stored Database
Example Database (University):
a.
Student: Name, StudentNumber,
Class, Major
b.
Course: CourseName,
CourseNumber, CreditsHours, Department
c.
Section: SectionIdentifier,
CourseNumber, Semester, Year, Instructor
d.
Grade_Report: StudentNumber,
SectionIdentifier, Grade
e.
Prerequisite: CourseNumber,
PrerequisiteNumber
Structure
4. Where are databases used today?

Communications

Networking

Transportation and Logistics

Financial Management

Knowledge-based Systems

Accessing literature

Healthcare

Scientific research (as well as all other types of research)
5. What are some typical DB applications?
a. Supermarket purchases

Inventory control

Price information

Threshold for restock

Discount notations
b. Credit card purchases

Sufficient credit?

Expired card?

Stolen card?

Automatic update of monthly credit line

Tracking your purchases for the month (perhaps for the year)

Add your purchase information to store data base
d. Travel reservations (what purposes?)
e. Bookstore purchases
f. ATM Machine Transactions
6. Characteristics of the Database Approach (Difference between traditional
file processing and database approach)
a. Redundancy
b. Self-Describing nature of a database system: complete definition or description of
the database structure and constraints are stored in the system catalog and the
information stored in the catalog is called meta-data.
c. Insulation between Programs and Data, and Data Abstraction: (structure)
program-data
independence,
abstraction: the characteristics
program-operation
independence,
data
that allow program-data independence,
program-operation independence.
d. Multiple views of the data
e. Sharing of data and multiuser transaction processing : concurrency control (online transaction processing(OLTP) application)
7.
Advantages of Using a DBMS
a.
Controlling
Redundancy:
duplication, wastage of storage space, inconsistent
b.
Restricting Unauthorized Access
c.
Providing Persistent Storage for
Program Objects and Data Structures: object-oriented database. OODB are
compatible with C++, Java.
d.
Permitting
Inferencing
and
Actions Using Deduction Rules
e.
Providing Multiple User Interfaces
f.
Representing
Complex
Relationships Among Data
g.
Enforcing
Integrity
Constraints:
change in the code due to constraint enforced.
h.
Providing Backup and Recovery
8. Actors on the scene:
Database Administrator
Database Designers
End users
Casual end users
Naïve or parametric end users
Sophisticated end users
Stand alone users
Software engineers
9. Workers behind the scene:
DBMS system designers and implementers Tool developers
Operators and maintenance personnel