How do you keep an indexeddb transaction alive?

Question

Instead of opening several transactions (read a table, write to a table, write to another table, etc) is it possible to do this all from a single transaction as long as you are using an appropriate IDBTransaction?

Mozilla says: "The only way to keep the transaction active is to make a request on it. When the request is finished you'll get a DOM event and, assuming that the request succeeded, you'll have another opportunity to extend the transaction during that callback." which is a little vague. Does that mean if I provide an event handler for the DOM callback that I can use the transaction at any point in that callback without ever having to worry about the transaction being closed?

https://developer.mozilla.org/en/IndexedDB/Using_IndexedDB#Adding_data_to_the_database

Answer 1

Short answer: If you provide an event handler for a "success" or "error" event, you can place a new request inside that event handler and not have to worry about the transaction getting automatically closed.

Long answer: Transaction committing should generally be completely transparent. The only rule is that you can't hold a transaction open while doing non-database "stuff". I.e. you can't start a transaction, then hold it open while doing some XMLHttpRequests, or while waiting for the user to click a button.

As soon as you stop placing requests against a transaction and the last request callback finishes, the transaction is automatically closed.

However you can start a transaction, use that transaction to read some data and then write some results.

So make sure that you have all the data that you need before you start the transaction, then do all reads and writes that you want to do in the request callbacks. Once you are done the transaction will automatically finish.