Database Management System and Data models- DBMS

   Database Management System (DBMS)

a)      Database management system is the process of maintain data logically in a centralized location.

b)      Now a day’s different DB engines are available in market

SQL Server

ORACLE

DB2

My SQL

Postgres SQL etc…

Each database contains its own advantages and comparing with other DBMS providers may have some disadvantages.

c)       In this we can make all users to use same data, so we can avoid waste of memory and space.

d)      Data locates in the format of tables.

e)      User can get data from the database and share the changes at any time.

f)       We can maintain the logs easily as user information clearly available in the DB system.

g)      Every DB engine maintains standards on security permissions. So it is not easy to violate the data.

Data models:

Data model is the process of design the template of the database. Mostly a DBA will take the responsibility design the model of the DB before creating. A data model is a collection of concepts and rules for the description of the structure of the database. Structure of the database means the data types, the constraints and the relationships for the description or storage of data respectively. 

Data models are different types:

Hierarchal model.

Network model.

Relational model.

A hierarchical database model is a data model in which the data is organized into a tree-like structure. The data is stored as records which are connected to one another through links. A record is a collection of fields, with each field containing only one value. The entity type of a record defines which fields the record contains.

In this each table contains relation with another table.

 

Network Data model:

In network data model, data stores in the format of records. Each record is the dependent on another record and vice versa.

 

Network Database vs. Hierarchical Database Model       

  

Network Database Model	Hierarchical Database Model
Many-to-many relationship	One-to-many relationship
Easily accessed because of the linkage between the information	Difficult to navigate because of its strict owner to member connection
Great flexibility among the information files because the multiple relationships among the files	Less flexibility with the collection of information because of the hierarchical position of the files

Relational data model:

In this model, data is organized in two-dimensional tables called relations. The tables or relation are related to each other. If you want to fill data in child table, related data must present in parent table.