Data Model in DBMS

data model

Data Model in DBMS-

Data model defines the all over structure of database. In data model defines hows database tables are connected with each other and hows they access data from each other. Data model is important for describing  all database design to developer or database designer mainly. Data model shows hows data will be saved in database and hows we handle that data for later use.

Data model uses a different symbols for indicating the database structure mainly. In real industry lots of data models are being used for data representation. The different types of data model is as fallows-

  1. Hierarchical Model
  2. Network Model
  3. Entity-Relationship Model
  4. Relational Model
  5. Object-Oriented Data Model
  6. Physical Data Model

Features of Data Model-

  1. Data model is a logical structure of database system
  2. It is consistent and maintain database re-usability.
  3. Data models is up to date for represent a relationships between data and table with each other.

Types of Data Models-

1. Hierarchical Model-

The hierarchical model is the simplest model in DBMS system. That model is represented as a tree structure. The hierarchical model structure mainly start with root node and connected to child nodes and parent nodes. This model easily represent the all over database relation in simplest manner. example display a food database relation to each other.

Hierarchical model

Advantages of Hierarchical Model-

  1. Very simple and easy to maintain.
  2. If change made in parent node then automatically change reflect in to child node.
  3. Relationship representation easy to understand.

Dis-Advantages of Hierarchical Model-

  1. That model not supported to complex data structures mainly.
  2. If parent node deleted the automatically child node deleted.

2. Network Model-

It is the extension model of hierarchical model. It is most popular model after hierarchical model. It is next extension of hierarchical model. In hierarchical model child node is only attached to single parent node but in network model the child node is join to 2 parent nodes mainly.

Network Model

Advantages of Network Model-

  1. Data accessing speed is larger than hierarchical model.
  2. If change made in parent node then automatically change reflect in to child node.

Dis-Advantages of Network Model-

  1. Complex relationship representation get complex in network model.

3. Entity-Relationship Model-

It is very simplest model to represent a complex database structure. It is as equal to Entity relationship diagram mainly. Developers are easily understand the formation of database designing if the representation do in ER model. In ER model use entity, attribute and relation symbols for indicating a relationships between tables to each other.

entity relationship model

Advantages of ER Model-

  1. It is easy to draw a complex relationships.
  2. Easy to handle.
  3. Easy to understand.

Dis-Advantages of ER Model-

  1. In that model some information get hide and abstract in designing.

4. Relational Model-

In that model mainly maintain relations of table with each other. In relational model use tables for representing information mainly. The all information is denoted in to row and columns. In relational model the data is saved in two-dimensional method means information saved in table in row and column format.

relational model

Advantages of Relational Model-

  1. It simple to handle.
  2. More scalable as compare other models.

Dis-Advantages of Relational Model-

  1. Complex calculations not handle well in manner.

 5. Object-Oriented Data Model-

In real world that model are mostly used for data connections. In that model data represented as a objects and that all data attached to one another with relation. In that model basically audio, video, images etc type data can be saved and represented. In object-oriented data model two or more objects are connected with each other.

object oriented model

Advantages of Object-Oriented Model-

  1. Manage complex data well in manner
  2. Suitable for digital data formation.

Dis-Advantages of Object-Oriented Model-

  1. Hard to maintain.
  2. Need expert to extract data.

6. Physical Data Model-

Physical data model defines all logical representation of database. In that consist of table designing , column name and their values . In physical model also indicating the relationship between primary and foreign key of each other.

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