using System.Data;
using Oracle.DataAccess.Client;
using Oracle.DataAccess.Types;

using (OracleCommand com = new OracleCommand()){
OracleConnection con = new OracleConnection();
con.ConnectionString = "User id=USERID;Password=PASSWORD;Data Source=DBNAME;";

con.Open();
OracleTransaction tra = con.BeginTransaction(IsolationLevel.ReadCommitted);

try
{
com.CommandText = "insert into TEST values(val1,va2)";
com.Connection = con;
com.Transaction = tra;
com.ExecuteNonQuery();
tra.Commit();
}
catch(System.Exception)
{
tra.Rollback();
throw;
}
finally
{
con.Close();
}
}