its about data models in DBMS.

1. Data Model shows the logical structure of a
database including relationship and constraints
that determine how data can stored and accessed.

2.  Structural part:-consisting of set of rules
according to which databases can be constructed.
 Manipulative Part:- define the types of
operations that are allowed on the data.
 Integrity Rules:- which ensure that data is
accurate.

3.  Entity:-Anything about which data are to be
collected and stored.
 Attribute:- A characteristic of an entity.
 Relationship:-An association among entities.
 One to one(1:1) relationship
 One to many(1:M) relationship
 Many to one(M:1) relationship
 Many to many(M:M) relationship

4.  Object Based Data Models
 Physical Data Models
 Record Based Logical Data Models

5.  It uses concepts such as Entities, attributes
and relationship.
 Types of object based models:
 Entity Relationship
 Object Oriented
 Semantics
 Functional

6.  It describe how data is stored in the
computer, representing information such as
record structures, record ordering and
access paths.
 Less no. of models are there.

7.  It is used to specify the overall logical
structure of the database and to provide a
higher level description of the
implementation.
 Structured database in fixed formats.

8.  Hierarchical Model
 Network Model
 Relational Model

9. HIERARCHICAL
DIAGRAM:
 Hierarchical model is one
of the oldest database in
which data is organized
into tree like structure.
 This model uses a one to
many (1:M) relationship
for data elements.
 Hierarchical database
were popular in early
database design, in the
era of mainframe
computers.

10.  Simplicity
 Data security
 Data Integrity
 Efficiency
 Complexity
 Not Flexible
 Dependence
 Extra Space

11. NETWORK MODEL
 In 1965 C.W.BACHMAN
developed the first
network data model to
present complex data
relationships more
effectively than
hierarchical model.
 In network model the
multiple parent-child
relationships are used.

12.  Conceptual Simplicity
 Capability
 Data Integrity
 Ease to access data
 Data Independence
 Complexity
 Confusion
 Lack of structural
Independence

13. RELATIONAL MODEL
 The most popular data
model in DBMS is the
relational data model .
 In this model ,data is
organized in the terms of
rows(tuple) and
columns(attributes) in a
table known as RELATION.
 The principal of relational
model were first outlined by
Dr.E.F.Codd.

14.  Conceptual Simplicity
 Structural
Independence
 Design Implementation
 Security
 Hardware Overheads
 Expensive
 Storage