You can connect your C# application to
data in a SQL Server database using the .NET Framework Data Provider for SQL
Server. The first step in a C# application is to create an instance of the
Server object and to establish its connection to an instance of Microsoft SQL
Server.
The SqlConnection Object is Handling
the part of physical communication between the C# application and the SQL
Server Database . An instance of the SqlConnection class in C# is supported the
Data Provider for SQL Server Database. The SqlConnection instance takes
Connection String as argument and pass the value to the Constructor statement.
Sql Server connection string
connetionString="Data Source=ServerName;
Initial Catalog=DatabaseName;User ID=UserName;Password=Password"
If you have a named instance of SQL
Server, you'll need to add that as well.
"Server=localhost\sqlexpress"
When the connection is established ,
SQL Commands will execute with the help of the Connection Object and retrieve
or manipulate the data in the database. Once the Database activities is over ,
Connection should be closed and release the Data Source resources .
cnn.Close();
The Close() method in SqlConnection
Class is used to close the Database Connection. The Close method rolls back any
pending transactions and releases the Connection from the SQL Server Database.
A Sample C# Program that connect SQL
Server using connection string.
using System;
using System.Windows.Forms;
using System.Data.SqlClient;
namespace WindowsApplication1
{
public partial class Form1 :
Form
{
public Form1()
{
InitializeComponent();
}
private void
button1_Click(object sender, EventArgs e)
{
string connetionString
= null;
SqlConnection cnn ;
connetionString = "Data
Source=ServerName;Initial Catalog=DatabaseName;User
ID=UserName;Password=Password"
cnn = new
SqlConnection(connetionString);
try
{
cnn.Open();
MessageBox.Show
("Connection Open ! ");
cnn.Close();
}
catch (Exception ex)
{
MessageBox.Show("Can not open connection ! ");
}
}
}
}
Connect via an IP address
connetionString="Data Source=IP_ADDRESS,PORT;
Network Library=DBMSSOCN;Initial Catalog=DatabaseName;
User ID=UserName;Password=Password"
1433 is the default port for SQL
Server.
Trusted Connection from a CE device
connetionString="Data Source=ServerName;
Initial Catalog=DatabaseName;Integrated Security=SSPI;
User ID=myDomain\UserName;Password=Password;
This will only work on a CE device
Connecting to SQL Server using windows
authentication
"Server= localhost; Database= employeedetails;
Integrated Security=SSPI;"
A sample c# program that demonstrate
how to execute sql statement and read data from SQL server.
using System;
using System.Windows.Forms;
using System.Data.SqlClient;
namespace WindowsApplication1
{
public partial class Form1 :
Form
{
public Form1()
{
InitializeComponent();
}
private void
button1_Click(object sender, EventArgs e)
{
string connetionString
= null;
SqlConnection
connection ;
SqlCommand command ;
string sql = null;
SqlDataReader
dataReader ;
connetionString =
"Data Source=ServerName;Initial Catalog=DatabaseName;User
ID=UserName;Password=Password";
sql = "Your SQL
Statement Here , like Select * from product";
connection = new
SqlConnection(connetionString);
try
{
connection.Open();
command = new
SqlCommand(sql, connection);
dataReader =
command.ExecuteReader();
while
(dataReader.Read())
{
MessageBox.Show(dataReader.GetValue(0) + " - " +
dataReader.GetValue(1) + " - " + dataReader.GetValue(2));
}
dataReader.Close();
command.Dispose();
connection.Close();
}
catch (Exception ex)
{
MessageBox.Show("Can not open connection ! ");
}
}
}
}
