[storm] Update or add pattern with Storm

[Jamu Kakar]

Hi Brad,

Brad Allen wrote:
> Is that the only way to get around this? It would be nice if I could 
> perform a database update without doing any select at all. Sometimes the 
> id value of the primary key is already available, and I just want to do 
> an update without selecting first.
> 
> In those situations, it would be nice if we could just do something like:
> 
> customer = Customer (id=123, first_name = u'Jack', last_name = u'Sparrow')
> 
> However, we can't use store.add for this object if we want it to 
> generate an update statement; Storm usually generates an insert 
> statement for store.add unless the object was already in the store as a 
> result of store.find or store.get.

You can use ResultSet.set to run an update without invoking object
creation and caching behaviour:

result = store.find(Customer, Customer.id=123)
result.set(last_name=u"Sparrow-Hawk")

If Store.find returns many rows, ResultSet.set will run an UPDATE
that affects all of them.

Thanks,
J.