4 Types of Database Models Class 12 Unit 2

In class 12 unit 2 Student must study 4 major types of database models these are Hierarchical, Network, Relational, Entity Relation Database Models.

Hierarchical database model

  • Oldest types of database models 

  • Data represented in the form or records 

  • All the data represented in the tree format. 

  • The relationship between the records is called the parent-child relationship in which any child record relates to only a single parent type record.

  • In this database system, the parent is top-level privileges, and the child is bottom-level privileges.  


  • It is the easiest models 

  • It has one or more attributes 

  • The searching is cast and easy if a parent is known 

  • It supports one to one and one to many relationships 

Dis Advantages 

  • Outdated database model

  • It does not support many to many relationships the dependency on the parent node is not beneficial always.

  • Depends on the parent node is not beneficial always. 

  • Increases redundancy.  

Network database models.

  • This is an extension of the Hierarchical model. 

  • Data is organized more like a graph and is allowed to have more than one parent node.

  • In this database model data is more related as more relationships are established in this database model.

  • A network database model consists of a collection of records that are interrelated to each other which the help of relationship. 

  • Each record has multiple fields and each field has only one data value.

Advantages of network database model

  • It accepts many to many relationships so it is more flexible 

  • The searching is faster because of multidirectional pointers 

  • The networks model is simple and easy to design 

  • It reduces redundancy because data should not be repeated if the same data is needed.

Disadvantages of network database models 

  • It is difficult to handle the relationship in complex programs 

  • There is less security because of sharing data. 

  • It increases the processing overhead due to the complex relationship.

Relational Database Model

  • In this model data present in the table.

  • A relational database contains one or more data categories in columns, also called attributes.

  • Each row, also called a record or tuple(a data structure consisting of multiple parts), contains a unique instance of data, or key, for the categories defined by the columns.

  • Each table has a unique primary key, which identifies the information in a table. 

  • The relationship between tables can then be set via the use of foreign keys -- a field in a table that links to the primary key of another table.

Advantage of Relational database model 

  • The breaking of a complex database table into a simple database table becomes possible.

  • Database processing faster than other models.

  • There is very low redundancy 

  • The integrity rules can easily be implemented.


  • It is more complex than other models 

  • There are too many rules because of the complex relationship 

  • It needs more powerful computers and data storage devices.

Entity-Relationship Database Model

ER database model is based on a perception of a real-world that contains a collection of basic objects called entities and of the relationships among these objects and characteristics of an entity. 

ER- database is an overall logical structure of a database that can be expressed graphically. 

ER models, also called an ER schema, are represented by ER diagrams.

ER modeling is based on two concepts:

  • Entities, defined as tables that hold specific information (data)

  • Relationships, defined as the associations or interactions between entities

Components of ER Database models: 

  1. Entity: things, objects, or sets of properties.   Donate by rectangle 

  2. Attribute: properties of an entity, element. Donate by oval

  3. Link: the flow of information. Donate by line

  4. Relationship: relation between several entities. Done by a diamond shape.

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