This document discusses different types of database management systems including hierarchical, network, entity-relationship, relational, and object-oriented databases. A database management system (DBMS) is software that allows users to create, organize, and manage databases and perform operations like creating, inserting, deleting, updating, and retrieving data. Each type of DBMS stores and connects data in a different way, with relational databases using tables to represent data and relationships and object-oriented databases representing entities as classes with attributes, behaviors, and communicating objects.
2. • DBMS is a software system for creating, organizing
and managing the database.
• It provides an environment to the user to perform
operations on the database for creation, insertion,
deletion, updating and retrieval of data.
4. HIERARCHICAL DATABASES
• Data is represented as a tree.
• A record type can belong to only one owner type but a owner
type can belong to many record type.
5. NETWORK DATABASES
• It is modified version of Hierarchical databases where it
allows more general connections among the nodes as well.
• They are difficult to use but are more flexible than
Hierarchical databases.
6. ENTITY-RELATIONSHIP DATABASES
• It is a high level database model based on the need of the
organization.
• Its entities are distinguishable from other objects and
relationship is an association among several entities.
7. RELATIONAL DATABASES
• It is a lower level database model that uses a collection of
tables to represent both data and relationships among those
data.
• Each table has multiple columns, depending on the number
of attributes, and each column has a unique name..
8. OBJECT-ORIENTED DATABASES
• It represents entity sets as class and a class represents both
attributes and the behavior of the entity.
• Instance of a class is an object.
• The internal part of the object is not externally visible.
• One object communicates with the other by sending
messages.
