N Tier(Multi-Tier), 3-Tier, 2-Tier Architecture with EXAMPLE
What is N-Tier?
An N-Tier
Application program is one that is distributed among three or more
separate computers in a distributed network.
The
most common form of n-tier is the 3-tier Application, and it is classified into
three categories.
- User interface programming in the user's
computer
- Business logic in a more centralized computer,
and
- Required data in a computer that manages a
database.
This
architecture model provides Software Developers to create Reusable
application/systems with maximum flexibility.
In N-tier,
"N" refers to a number of tiers or layers are being used
like – 2-tier, 3-tier or 4-tier, etc. It is also called “Multi-Tier Architecture”.
The
n-tier architecture is an industry-proven software
architecture model. It is suitable to support enterprise level client-server
applications by providing solutions to scalability, security, fault tolerance,
reusability, and maintainability. It helps developers to create flexible and
reusable applications.
In
this tutorial, you will learn-
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N-Tier Architecture
A
diagrammatic representation of an n-tier system depicts here – presentation,
application, and database layers.
N Tier Architecture Diagram
These
three layers can be further subdivided into different sub-layers depending on
the requirements.
Some
of the popular sites who have applied this architecture are
- MakeMyTrip.com
- Sales Force enterprise application
- Indian Railways – IRCTC
- Amazon.com, etc.
Some
common terms to remember, so as to understand the concept more clearly.
- Distributed Network: It is a network architecture, where the
components located at network computers coordinate and communicate their
actions only by passing messages. It is a collection of multiple systems
situated at different nodes but appears to the user as a single system.
- It provides a single data communication
network which can be managed separately by different networks.
- An example of Distributed Network– where
different clients are connected within LAN architecture on one side and
on the other side they are connected to high-speed switches along with a
rack of servers containing service nodes.
- Client-Server Architecture: It is an architecture model where the client
(one program) requests a service from a server (another program) i.e. It
is a request-response service provided over the internet or through an
intranet.
In
this model, Client will serve as one set of program/code which
executes a set of actions over the network. While Server, on the
other hand, is a set of another program, which sends the result sets to the client
system as requested.
- In this, client computer provides an
interface to an end user to request a service or a resource from a server
and on the other hand server then processes the request and displays the
result to the end user.
- An example of Client-Server Model– an ATM
machine. A bank is the server for processing the application within the
large customer databases and ATM machine is the client having a user
interface with some simple application processing.
- Platform: In computer science or software industry, a
platform is a system on which applications program can run. It consists of
a combination of hardware and software that have a built-in instruction
for a processors/microprocessors to perform specific operations.
- In more simple words, the platform is a
system or a base where any applications can run and execute to obtain a
specific task.
- An example of Platform – A personal machine
loaded with Windows 2000 or Mac OS X as examples of 2 different
platforms.
- Database: It is a collection of information in an
organized way so that it can be easily accessed, managed and updated.
- Examples of Database – MySQL, SQL Server,
and Oracle Database are some common Db's.
Types of N-Tier Architectures
There
are different types of N-Tier Architectures, like 3-tier Architecture,
2-Tier Architecture and 1- Tier Architecture.
First,
we will see 3-tier Architecture, which is very important.
3-Tier Architecture
By
looking at the below diagram, you can easily identify that 3-tier
architecture has three different layers.
- Presentation layer
- Business Logic layer
- Database layer
3 Tier Architecture Diagram
Here
we have taken a simple example of student form to understand all these three
layers. It has information about a student like – Name, Address, Email, and
Picture.
User
Interface Layer or Presentation Layer
Presentation
Layer
private void
DataGrid1_SelectedIndexChanged(object sender, System.EventArgs e)
{
// Object of the
Property layer
clsStudent
objproperty=new clsStudent();
// Object of the
business layer
clsStudentInfo
objbs=new clsStudentInfo();
// Object of the
dataset in which we receive the data sent by the business layer
DataSet ds=new
DataSet();
// here we are placing
the value in the property using the object of the
//property layer
objproperty.id=int.Parse(DataGridl.SelectedItem.Cells[1].Text.ToString());
// In this following
code we are calling a function from the business layer and
// passing the object
of the property layer which will carry the ID till the database.
ds=objbs.GetAllStudentBsIDWise(objproperty);
// What ever the data
has been returned by the above function into the dataset
//is being populate
through the presentation laye.
txtId.Text=ds.Tables[0].Rows[0][0].ToString();
txtFname.Text=ds.Tables[0].Rows[0][1].ToString();
txtAddress.Text=ds.Tables[0].Rows[0][2].ToString();
txtemail.Text=ds.Tables[0].Rows[0][3].ToString();
Code
Explanation
- The above code defines the basic designing of
a front end view of applications as well as calling of the functions of
other layers so that they can be integrated with each other.
Business
Access Layer -
This
is the function of the business layer which accepts the data from the
application layer and passes it to the data layer.
- Business logic acts as an interface between
Client layer and Data Access Layer
- All business logic – like validation of data,
calculations, data insertion/modification are written under business logic
layer.
- It makes communication faster and easier
between the client and data layer
- Defines a proper workflow activity that is
necessary to complete a task.
// this is the function
of the business layer which accepts the data from the
//application layer and
passes it to the data layer.
public class
clsStudentInfo
{
public DataSet GetAllStudentBsIDWise(clsStudent obj)
{
DataSet ds=new DataSet();
ds=objdt.getdata_dtIDWise(obj);// Calling of
Data layer function
return ds;
}
}
Explanation
of code
The
code is using the function of business layer, which will accept the data for
the application layer and passed it to the data layer. The Business layer codes
act as a mediator between the functions defined in the presentation layer and
data layer and calling the functions vice -versa.
Data
Access Layer
This
is the data layer function, which receives the data from the business layer and
performs the necessary operation into the database.
// this is the
datalayer function which is receiving the data from the business
//layer and performing
the required operation into the database
public class
clsStudentData // Data layer class
{
// object of property layer class
public DataSet getdata_dtIDUise(clsStudent obj)
{
DataSet ds;
string sql;
sql="select *
from student where Studentld=" +obj.id+ "order by Studentld;
ds=new DataSet();
//this is the datalayer function which accepts the sql query
and performs the
//corresponding operation
ds=objdt.ExecuteSql(sql);
return ds;
}
}
Explanation
of code
The
code defines in dataset layer above accepts the entire request: requested by the
system and performing the required operations into the database.
2-Tier Architecture:
It
is like Client-Server architecture, where communication takes place between
client and server.
In
this type of software architecture, the presentation layer or user interface
layer runs on the client side while dataset layer gets executed and stored on
server side.
There
is no Business logic layer or immediate layer in between client and server.
Single Tier or 1-Tier Architecture:
It
is the simplest one as it is equivalent to running the application on the
personal computer. All of the required components for an application to run are
on a single application or server.
Presentation
layer, Business logic layer, and data layer are all located on a single
machine.
Advantages and Disadvantages of Multi-Tier
Architectures
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Disadvantages |
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Hence,
it is a part of a program which encrypts real-world business problems and
determines how data can be updated, created, stored, or changed to get the
complete task done.
N-Tier Architecture Tips and Development
Considering
the software professionals must have a full control on all the layers of the
architecture, tips on n-tier architecture are given as below
1. Try to decouple layers from another layer as much
as possible by using a technique like soap XML.
2. Use some automated tools to generate a mapping
between a business logic layer and a relational database layer (data layer).
Tools that can help in modelling these mapping techniques are – Entity
Framework and Hibernate for .Net etc.
3. In client presenter layer, put a common code for
all the clients in a separate library as much as possible. This will maximize
the code reusability for all types of clients.
4. A cache layer can be added into an existing layer
to speed up the performance.
Summary:
The
N-tier architecture helps to manage all the components (business layer,
presentation layer, and database layer) of an application under one roof.
Applications
that uses small numbers of users on a local area network can benefit from
n-tier architecture.
Such
architectural design ascertains maintaining, scaling up and deploying an
application on the Internet efficiently.
, 3-Tier, 2-Tier Architecture with EXAMPLE){kind=link}
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