2- Tier Architecture
Client/server applications started with a simple, 2-tiered model consisting of a client and an application server.
The most common implementation is a ‘fat’ client – ‘thin’ server architecture, placing application logic in the client.
The database simply reports the results of queries implemented via dynamic SQL using a call level interface (CLI) such as Microsoft’s Open Database Connectivity (ODBC).
It is client server architecture which can have direct communication and run faster (tight coupled)
2 tier architecture has two parts
1. Client application (client tier).
2. Database (data tier).
On client application side the code is written for saving the data in the SQL server database.
Easy to maintain and modification is bit easy
Communication is faster
Performance will decreased if user increases
The problem with the Two Tier Architecture is the server cannot respond to multiple requests at the same time which causes data integrity issues.
3 – Tier Architecture
The components of three-tiered architecture are divided into three layers: a presentation layer, functionality layer, and data layer, which must be logically separate.
The 3-tier architecture attempts to overcome some of the limitations of 2-tier schemes by separating presentation, processing, and data into separate distinct entities.
The middle-tier servers are typically coded in a highly portable, non-proprietary language such as C. Middle-tier functionality servers may be multithreaded and can be accessed by multiple clients, even those from separate applications.
Web based application which can have three layers
1. Client layer
UI part of application used to design where data is presented and input is taken from user.
2. Business layer
Here calculation, insertion and modification can be done.
Makes communication faster between client and data layer
3. Data layer
the actual database is data layer, perform insert, update, delete, get data from database based on input.
Middleware is used to communicate faster.