Hi Friend this very simple program : How to Connect to Database using C#
using System;
usingSystem.Collections.Generic;
usingSystem.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
usingSystem.Windows.Forms;
usingSystem.Data.SqlClient; // SQL Server Connection
usingSystem.Data.OleDb; //Access Databse Connection
usingOracle.DataAccess.Client; //Oracle Databse Connection
//Oracle Connection add a reference of the assembly Oracle.DataAccess.dll.
namespaceHowToConnectSqlDatabase
{
publicpartial class Form1 : Form
{
publicForm1()
{
InitializeComponent();
}
//Access Database Connection
privatevoid AccessDatabase_Click(object sender, EventArgse)
{
OleDbConnectionOleCnn =new
OleDbConnection(“Provider=Microsoft.ACE.OLEDB.12.0;Data Source=”
+@”C:Northwind 2007.accdb”);
OleDbCommandOldcmd;
try
{
OleCnn.Open();
Oldcmd = new OleDbCommand(“SELECT * From Employees”,OleCnn);
Oldcmd.ExecuteNonQuery();
MessageBox.Show(“Success”);
OleCnn.Close();
}
catch(Exception ex)
{
MessageBox.Show(ex.Message);
}
}
//SQL Server Database Connection
private void SQLServer_Click(objectsender, EventArgs e)
{
SqlConnection cnn = new SqlConnection(“Data Source=ServerName;Initial
Catalog=Databasename;Integrated Security=True”);
SqlCommand cmd;
try
{
cnn.Open();
cmd = new SqlCommand(“SELECT * From Employees”,cnn);
cmd.ExecuteNonQuery();
MessageBox.Show(“Success”);
cnn.Close();
}
catch(Exception ex)
{
MessageBox.Show(ex.Message);
}
}
//Oracle Database Connection
private void Oracle_Click(objectsender, EventArgs e)
{
OracleConnection Oracnn = new OracleConnection(“User ID=hr;Password=hr;Data
Source=ServerName;”);
OracleCommand OraCmd;
try
{
Oracnn.Open();
OraCmd = new OracleCommand(“SELECT * From Employees”, Oracnn);
OraCmd.ExecuteNonQuery();
MessageBox.Show(“Success”);
Oracnn.Close();
}
catch(Exception ex)
{
MessageBox.Show(ex.Message);
}
}
}
}
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