[whatwg] SQL API and Transactions
beidson at apple.com
Thu Oct 25 20:33:21 PDT 2007
I still like the new API, but have a detail to nitpick on.
The fact that my most noteworthy complaint is this nitpick indicates
how solid the API is, I think ;)
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
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
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
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