3 Tier Architecture in DBMS

Components of 3 tier architecture 

1. Client-side : 

• • It is nothing but the presentation layer (your PC, Tablet, Mobile, etc.) 
  • It sends a request to the server-side via the application server layer

2. Application server : 

• • It is present as an intermediate tier between the client and server tires
  • Unlike two-tier architecture, in this requests are not directly sent from the client to the server-side, when a client sends a request first it is transferred to the application server then this application server  transfers the request to the server-side, followed by query processing and transaction management
  • This intermediate layer also acts as a senses medium for the exchange of partially processed data between server and client

3. Server-side:

• • Nothing but the database of the server-side application 
  • It sends responses to the requests received from the client-side to the application server and the application server, in turn, transfer them to the client-side.

Examples of three-tier architecture 

• All large dynamic web applications  present over the internet or examples of this 3 tier architecture 
• A large website like prepinsta.com over the internet is the best example, isn’t it?? 

Purpose of three-tier architecture 

• Integrity: because of the middle layer between the client and server-side data  corruption can be removed 
• Security: as there is no direct interaction between client and server we can restrict unauthorized access if any 
• To provide a clear separation between the user application and physical database
• Program data independence and multiple views of data 
• Because of the above features, a large number of users can access a database easily 

Demerits 

• There might be complexity in implementation and communication 
• Sometimes it becomes difficult for interaction due to the presence of middle layers and responses may be delayed but they can be easily overcome by efficient server administration.