Question

Consider the following code which does not rollback the transaction if an exception is caught.

transaction = connection.BeginTransaction();
command.Transaction = transaction;
try {
    // interact with database here
catch {}
finally {
    connection.Close();
}

What are the consequences of this and is it necessary to rollback the transaction?

Answer 1

It will leave an open transaction on the database, which could potential block other queries.

Taken from here:

Consider the following general
guidelines when you use transactions
so that you can avoid causing
deadlocks:

• Always access tables in the same order
  across transactions in your
  application. The likelihood of a
  deadlock increases when you access
  tables in a different order each time
  you access them.

• Keep transactions as
  short as possible. Do not make
  blocking or long-running calls from a
  transaction. Keep the duration of the
  transactions short. One approach is to
  run transactions close to the data
  source. For example, run a transaction
  from a stored procedure instead of
  running the transaction from a
  different computer.

• Choose a level of
  isolation that balances concurrency
  and data integrity. The highest
  isolation level, serializable, reduces
  concurrency and provides the highest
  level of data integrity. The lowest
  isolation level, read uncommitted,
  gives the opposite result.