Question

How can I determine that particular query will change the state of DB?
I use JDBC. Should I use parsing searching for key words like INSERT, DELETE or there are some other ways?

Answer 1

One way:

1. Execute the query
2. Check the update count
3. If updates are made, do your user check
4. On a positive response, commit the transaction. On negative, roll it back.

There would be variations. Explore the Statement API to get a feel for your options.

Edit: Ensure autocommit is off, or transactionality is out the window!

More edit: As pointed out by commenters, this isn’t a scalable solution. For scalability, transactions have to be kept short, and you don’t want to have user think time during an open transaction. If there will be multiple users, find a way to do this that doesn’t involve holding a transaction open, perhaps with some creative use of statement caching and rollbacks/commits. For better advice, explain more about your requirements.