Difference between web and desktop applications in database access

Question

i have a bit theoretical question.

When creating web applications, there is difference to desktop applications with working and active connection to database. So im curious if there is some solution, which can provide more desktop-like access to database e.g. transactions on asynchronous requests from client (web browser)?

edit: So i figured out, that there can be a transaction process of asynchronous request, from client. Is there solution, which can provide it in web apps?

e.g I have assynchronou ajax call, which consist of multiple operations, and i wana to process them as transaction. If everything is okay, operations will be all done. But if one of them fail, just rollback it. Like its in DB. Is it possible?

edit2: maybe im wrong and the issue is not about ajax, but about whole web applications, but i dont think there is a way how to make a asynchronnous request from web client.

Answer 1

Transaction need continuous connection to database. To make it work with web application you need a platform which allow the application to run continuously independent of client request. Java servlet is best fit, php is a no-no. So I asume you will use java servlet.

In java servlet, you can create a db transaction, create an id for it, and then store them in a static variable or in the provided application-wide object, context. Then, return the id to the client.

When the client want to send another request, make it send the id. The application then can locate the transaction variable based on the id. As long as the application doesn't restarted between the two requests, the transaction is still there and active.

Because web application don't know when the user leave the application, you must create a mechanism to check the transactions periodically, and then rollback it if the user leave them for a specified time period.

Answer 2

The database has no knowledge of who is connected outside of authentication.