Wednesday, July 31, 2019

Database Models

Database Models

Database model defines the logical style and structure of a Database and define however information are going to be hold on, Accessed and updated during a database management system.
While the Relational  model is most generally used Database model there are some other models too.
1) Hierarchical Model
2) Network Model
3) Relational Model
4) Entity Relationship Model
5) Object Oriented Model

1) Hierarchical Model

Hierarchical Model 

This Database model organizes information into tree like structure with one root to that all the other information and expends like a tree, having child node to the parent node. during this model with efficiency describes several real-world relationships like index of a book, recipes etc. during a hierarchical model, Data or information is organized into tree structure with one-many relationship between two different type of information. For ex: - one department will have several courses, professors and off course several students.
A hierarchical Database is a kind of DBM (Database Management) System that links record along during a tree data structure such each record type has only one owner.

2) Network Model- (Relationship level increase)

Network Model- (Relationship level increase)

Network Model is an extension of the hierarchical model. during this information is organized additional like a graph and are allowed to have over one parent node. during this Database model, Data or information is more related, has additional relationship, has stablished. during this Database model also as the information is additional related has accessing the information is also easier and quick. This was the most wide used Database model before Relational model was introduced.

3) ER Model: -

ER Model

In this Database model relationships are created by dividing objects of interest into entity and its characteristics and attributes.
Different entities are related using relationships.
ER model are defined to represent the connection into ER model are defined to represent the connection into pictorial form to create it easier for various state holders to understand.
This model is good to style a Database which may then be converted into table during a relationship model.
This model is good to style a information which may then be be converted into table during a relationship model.
For example: -
If we've to design a college Database then the college can an entity with attributes (name, age, address etc.)
As the address is mostly complicated, it is another entity with the attributed (street name, pin code, city) and there'll be a relationship between them.

4) Relational Model: -

Relational Model

In this model, Data or information is organized in 2dimensional table and relationship is maintained by storing a common field.
This model was introduced by EF codd in 1970 and since then it has been the most wide used Database model. the fundamental structure of the information in relational model is table. All the data associated with a specific type is hold on in rows of that table. Hence, table is also called relation in relational model.

5) Object Oriented Data Model: -

Object oriented model is an extension of ER Model with facilities and object identity. OO Model represent an entity as a class.
The class represents both object attributes as well as the behavior of the entity. The OO Database management is suited for multimedia application as well as data with complex relationship that are difficult to model or process in a relation DBMS.

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