Evolution of DBMS
The chronological order of the development of DBMS is as follows
- Flat Files (1970s-1990s)
2. Hierarchical (1970s-1990s)
3. Network (1970s- 1990s)
4. Relational (1980s-present)
5. Object-Oriented (1990s- present)
6. Object-Relational (1990s-present)
7. Web enabled (1990s-present)
- Flat Files (1970s-1990s) :
File based system was the predecessor of the DBMS
Flat files database is a database that stores information in a single file or table.
In text file, every line is a record.It consists of fields that are separated by commas, whitespaces, tabs or any other character.
2.Hierarchical (1970s-1990s) :
Hierarchical database contains data in a hierarchically-arranged data.
It can be imagined as a family tree where there is a parent and a child relationship.
It can parent can have many children but one child can only have one parent ex : one-to-many relationship.
In Hierarchical database , rows of table represent the records and columns represent the attibutes.
3.Network database (1970s -1990s) :
This model is invented by Charles Bachmann.
The network database allows multiple parent and child relationships — — -ex : it maintains many-to many relationship.
Network database is basically a graph structure.
In a network database a relationship is a referred to as a set.Each set comprises of two types of records,an owner record and a member record.
4.Realationl database (1980s-present) :
Relationship database model was proposed by E. F. Codd.
It is most famous data model and is uses by the most of people arround the world.
Here,data are structured into tables (“relations”) consisting of rows and columns.
Each row is called a record and it consists number of attributes organized in columns.
5.Object — oriented database (1990s -present) & 6. Object- relationship database (1990s-present) :
In OO_DBMS and OR_DBMS,the data or information is presented in the form of objects, much like in object oriented programming language.
OO_DBMS and OR_DBMS implement object oriented concepts such as classes of objects,object identity,polymorphism,encapsulation, and inheritance.
An object oriented database stores complex data as compared to relational database.
7. Web enabled (1990s-present) :
A Web enabled database is a databse application designed to be managed and accessed through the internet.