In the above diagram, “cn” is an object, that is able to maintain the connection with the database.
The cn is an object for “Connection” class (SqlConnection or OleDbConnection).
Import the API:
using System.Data.SqlClient;
Prepare the Connection string:
string cnstr = “data source=<name of the server>;user id=<user name>;password=<password>;initial catalog=<database name>”;
Construct the “Connection” class object:
SqlConnection cn = new SqlConnection(cnstr);
Open the connection:
cn.Open();
Close the connection:
cn.Close();
Import the API:
using System.Data.OleDb;
Prepare the Connection string:
Oracle
string cnstr = “provider=oraoledb.oracle.1;data source=<name of the server>user id=<user name>;password=
MS Access
string cnstr = “provider=microsoft.jet.oledb.4.0;data source=<path of the db file>”;
Construct the “Connection” class object:
OleDbConnection cn = new OleDbConnection(cnstr);
Open the connection:
cn.Open();
Close the connection:
cn.Close();
using System.Data.SqlClient;
using System.Data.OleDb;
private void btnSqlServer_Click(object sender, EventArgs e)
{
string cnstr = "data source=.;user id=sa;password=123;initial catalog=master";
SqlConnection cn = new SqlConnection(cnstr);
cn.Open();
MessageBox.Show("Successfully Connected with Sql Server");
cn.Close();
}
private void btnOracle_Click(object sender, EventArgs e)
{
string cnstr = "provider=oraoledb.oracle.1;data source=.;user id=scott;password=tiger";
OleDbConnection cn = new OleDbConnection(cnstr);
cn.Open();
MessageBox.Show("Successfully Connected with Oracle");
cn.Close();
}
private void btnMSAccess_Click(object sender, EventArgs e)
{
string cnstr = "provider=microsoft.jet.oledb.4.0;data source=c:\\database1.mdb";
OleDbConnection cn = new OleDbConnection(cnstr);
cn.Open();
MessageBox.Show("Successfully Connected with MS Access");
cn.Close();
}