Use the Using statement with disposable objects. In particular with any kind of connection and datareaders
string oradb = "Data Source=ORCL;User Id=hr;Password=hr;";
using(OracleConnection conn = new OracleConnection(oradb))
using(OracleCommand cmd = new OracleCommand())
{
conn.Open();
cmd.Connection = conn;
cmd.CommandText = "select * from departments";
cmd.CommandType = CommandType.Text;
using(OracleDataReader dr = cmd.ExecuteReader())
{
dr.Read();
label1.Text = dr.GetString(0);
}
}
Here you could read about the Using statement and why it is important. Regarding the connection and readers, you should enclose the objects with the using statement to be sure that everything is properly closed and disposed when you exit from the using block ALSO in case of exceptions