The document discusses different types of data models including logical, physical, and record-based models. It describes key concepts of data models like entities, attributes, relationships and different relationship types. Specific models covered are hierarchical, network, and relational with details on their structure, advantages and disadvantages.

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