MBA (General) - IV Semester, Information Technology and E-Business, Unit 2.1
Brief History of Database Systems
1940’s, 50’s Initial use of computers as calculators. Limited data, focus on algorithms. Science, military applications.
Brief History of Database Systems
1940’s, 50’s Initial use of computers as
calculators. Limited data, focus on algorithms. Science, military applications.
1960’s Business uses. Organizational data,
customer data, sales, inventory, accounting, etc. File system based, high
emphasis on applications programs to extract and assimilate data. Larger
amounts of data, relatively simple calculations.
1970’s the relational model. Data separated
into individual tables. Related by keys. Initially required heavy system
resources. Examples Oracle, Sybase, Informix, Digital RDB, IBM DB2.
1980’s Microcomputers - the IBM PC, Apple
Macintosh. Database program such as dbase (sort of), Paradox, Foxpro, MS
Access. Individual user can create, maintain small databases.
Late- 1980’s Local area networks. Workgroups
sharing resources such as files, printers, e-mail.
Client/Server Database resides on a central
server, applications programs run on client pc attached to the server over a
LAN.
1990’s Internet and World Wide Web make
databases of all kinds available from a single type of client - the Web
Browser. Data warehousing and Data Mining also emerge.
Other types of Databases
Object-Oriented Database Systems. Objects (data
and methods) stored persistently.
Distributed Database Systems. Copies of data
reside at different locations for redundancy or for performance reasons.
Appropriate Use for a Database
In addition to the advantages already mentioned
Performance
Expendability, Flexibility, Scalability
Reduced application development times
Standards enforcement
However, keep in mind
DBMS has High initial cost (although falling)
DBMS has High Overhead - requires powerful
computers
DBMS are not special purpose software programs.
E.g, contrast a canned accounting software package like Quicken or QuickBooks
with DBMS like MS Access.
When is a DBMS Not Appropriate?
Database is small with a simple structure
Applications are simple, special purpose and
relatively static.
Applications have real-time requirements.
Example
Traffic signal control
ECU patient monitoring
Concurrent, multi-user access to data is not
required.
A Database contains
User Data
Metadata
Indexes
Application metadata
