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Title: History of dbms
Description: i made this pdf as an assignment. this content all about history of database management systems.
Description: i made this pdf as an assignment. this content all about history of database management systems.
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History of Database Systems
By
Kaushalya Dharmarathna(030087)
Sandun Weerasinghe(040417)
Early Manual System
Before-1950s
Data was stored as paper records
...
Lot of time was wasted
...
g
...
1
Revolution began
1950s and early 1960s:
Data processing using magnetic tapes for
storage
Tapes provide only sequential access
Punched cards for input
Late 1960s and 1970s:
Hard disks allow direct access to data
Data stored in files
Known as File Processing System
File based systems
Adequate for small applications
Drawbacks
Separation and isolation of data
Each program maintains its own set of
data
...
2
File based systems (contd
...
Wasted space and potentially different
values and/or different formats for the
same item
...
File based systems (contd
...
Fixed Queries/Proliferation of
application programs
Programs are written to satisfy particular
functions
...
3
Database Approach
Arose because:
Definition of data was embedded in application
programs, rather than being stored separately
and independently
...
Result:
The database and Database Management
System (DBMS)
...
)
5
Network Model
Supported more complex relations
Physical file pointers were used to
model the relations between files
Relations had to be decide in
advance
Most suitable for large databases
with well defined queries and welldefined applications
...
)
Authors
Subjects
Books
Publishers
6
Relational Model (1970’s)
E
...
Codd introduced the relational
model in 1970
Provides a conceptually simple
model for data as relations
(typically considered “tables”) with
all data visible
...
)
7
Relational Model (Contd
...
Extend the entity-relationship data
model by including encapsulation,
methods and object identity
8
Object-relational models
Extend the relational data model by
including object orientation and
constructs to deal with added data types
...
Preserve relational foundations, in
particular the declarative access to data,
while extending modeling power
...
Examples:
Oracle (Oracle Corporation)
Ingres (Computer Associates)
SQL Server (Microsoft Corporation)
Access (Microsoft Corporation)
IMS, DB2 (IBM)
And many more…
9
Title: History of dbms
Description: i made this pdf as an assignment. this content all about history of database management systems.
Description: i made this pdf as an assignment. this content all about history of database management systems.