while (reader.Read()) Console.WriteLine($"reader["first_name"] reader["last_name"]");

conn.Open(); using (OracleBulkCopy bulkCopy = new OracleBulkCopy(conn))

using (OracleDataReader reader = cmd.ExecuteReader())

while (reader.Read()) Console.WriteLine(reader["last_name"]);

bulkCopy.DestinationTableName = "TEMP_EMPLOYEES"; bulkCopy.BatchSize = 500; bulkCopy.WriteToServer(dt);

conn.Open(); OracleTransaction tx = conn.BeginTransaction(); try OracleCommand cmd = conn.CreateCommand(); cmd.Transaction = tx; cmd.CommandText = "UPDATE accounts SET balance = balance - 100 WHERE id = 1"; cmd.ExecuteNonQuery(); cmd.CommandText = "UPDATE accounts SET balance = balance + 100 WHERE id = 2"; cmd.ExecuteNonQuery(); tx.Commit(); catch tx.Rollback(); throw;