Problem In Update Due To Transaction Presence.

Hi, 
Good morning to all. I'm facing the following problem. Can anyone please help me!...When a transaction is open, the database is getting locked for other user to fetch the records from database.I have to update multiple database table with huge data (Lac). So the transaction will be open for longer period. Mean while if somebody tries to fetch or do select query it give timeout exception. And it does not function until the transaction is closed.How to avoid this database locking for other users. Below is the code that i have used:            using (DbConnection dbconn = base.db.CreateConnection())
            {
                dbconn.Open();
                DbTransaction dbtran = dbconn.BeginTransaction();
                try
                {            
                   
                    Here inserting, updating to multiple table will be happening
                    dbtran.Commit();

                }
                catch (SqlException ex)
                {
                    dbtran.Rollback();

                }
                finally
                {
                    dbconn.Close();
                }
            }    
 Thanks in advance... :)
Regards,
Ashok kumar.