[whatwg] SQL API and Transactions

[Ian Hickson]

On Thu, 25 Oct 2007, Brady Eidson wrote:
> 
> For major steps during processing of a transaction, if that step fails 
> the SQLTransactionErrorCallback is invoked.
> 
> Additionally, for each statement processed within a transaction, success 
> and failure in executing that statement both result in a callback - 
> SQLStatementCallback and SQLStatementErrorCallback respectively.
> 
> With the above mechanisms, there is a lot of solid notification to the 
> script about progress of a transaction.  There seems to be a flaring 
> hole, however.
> 
> Step 9 of the transaction steps stipulates that if the transaction fails 
> to commit, the script will get an SQLTransactionErrorCallback indicating 
> this failure.  However, there is no final callback indicating *success* 
> of the commit.
> 
> In the case of a general transaction used for a chain of executeSql 
> calls, the script will have gotten a callback for each statement as it 
> succeeds and therefore might assume the transaction will succeed.  
> However, they don't know *when* is has succeeded.
>
> In the case of the transaction wrapped by a changeVersion() call, the 
> script will definitely know when the changeVersion() fails, but will not 
> know at what point in time the changeVersion() has finished and the data 
> is all committed to disk.
> 
> I can see a script wanting to know when a transaction is actually 100% 
> complete and committed before moving on to the next task.  I just don't 
> know how important it is, and wanted to bring this point up for 
> discussion.

We can add a third callback to changeVersion() and transaction(). I can't 
see any other way to solve it. What do people think? Too heavy-weight, or 
ok? I'm ok with doing it if people want it.

-- 
Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'