Data Models

Data Models

There are different types of the data models and now let see each of them in detail...

• file based model
• Hierarchical model
• Network model
• Relation model
• Object oriented data model

Let us explain all these types of data models in DBMS..

file based model

Data was maintained flat file.that is a punched card technology.

Advantage

• Various access method

Disadvantage

• Separation and Isolation
• Duplication of data weak security

Hierarchical model

In this files are related in a parent/child manner with each child file having at most one parent file.

Advantage 

• Efficient searching
• Less redundant data
• Data independence
• Data security and integrity

Disadvantage

• Complex implementation
• Can't easily handle
• Many to many relationship

Network model

Network data model files are related as owner and members similar to the common network model expect that each member file can have more than one owner.

Advantage 

• Data access flexibility
• Promotes database integrity
• Data independence
• Handle more relationship types

Disadvantage

• Difficult to design and maintains
• Lack of structural independence

Relation model

Relation model represents the database as a collection of relations. a relation is table of values.

every row in the table represents a collection of related data values. 

It can be defined using the following two terminologies..

• Instance - a table with rows and columns
• Schema - Specifies the structure

Some popular Relational Database management systems are,

• IBM
• Oracle
• Microsoft SQL Server 

Advantage 

• Simplicity
• Structural Independence
• Easy to use
• Query capability
• Data independence

Disadvantage

• Implementation complexity
• Database management problem-maintaining difficult
• Lack of structural independence
• programming complexity

Object oriented data model

It supports the modeling and creation of the data as object.

Advantage 

• Can efficiently manage a large number of different data types.
• Semantic content added
• Visual representation includes semantic content
• Inheritance promotes data integrity

Disadvantage

• Complex navigational system
• Learning curve is step