Oracle database automatically adds 1

Method 1
/// Query the record serial number and Add 1

Public int RecnoSelect (string strSq1)
{
// Record serial number
Int r = 0;
String t = "";
OracleCommand cmd = null;
Cmd = new OracleCommand ();
Cmd. Connection = conn;
Cmd. CommandText = strSq1;
Conn. Open ();
Object obj = cmd. ExecuteScalar ();
If (obj! = Null)
{
T = obj. ToString ();
R = Convert. ToInt32 (t );
R ++;
}
Conn. Close ();
Cmd. Dispose ();
Return r;
}
/// Add 1 and modify the record sequence number
Public void RecnoUpdate (string strSq2)
{
OracleCommand cmd = null;
Cmd = new OracleCommand ();
Cmd. Connection = conn;
Cmd. CommandText = strSq2;
Conn. Open ();
Cmd. ExecuteNonQuery ();
Conn. Close ();
Cmd. Dispose ();

}
String strSq1 = "Select RECORD1 From T_RECORD ";
Int r = operate. RecnoSelect (strSq1 );
String strSq2 = String. Format ("Update T_RECORD Set RECORD1 = '{0}'", r );
Operate. RecnoUpdate (strSq2 );
Method 2

INSERTINTO T_table (Record_no) Values (s_zg_operation.nextval );