[erlang-questions] mnesia:update_element

[Musumeci, Antonio S]

Obviously there are ways to simulate it but there are situations where you don't care to read then write in a transaction. Where you could do a dirty read and then a dirty update_element. That's going to be faster than dirty read, transaction(wread + write).

-----Original Message-----
From: erlang-questions@REDACTED [mailto:erlang-questions@REDACTED] On Behalf Of Pascal Chapier
Sent: Wednesday, September 15, 2010 4:44 AM
To: erlang-questions@REDACTED
Subject: [erlang-questions] mnesia:update_element


Hello,

Concerning Mnesia there is a powerful update mechanism with:
  mnesia:transaction(UpdateFunc(Parameters)),


I am not sure that one can find a simpler and more general update(Element) model for actions such as

   add to cart

   remove from cart

   apply 10% discount

   modify phone number...

it can be faster in some cases:

mnesia:dirty_read, updateFunc, mnesia:dirty_write if concurrency is not a problem,

mnesia:dirty_write(#my_table{key = Key, item=Value}), if only item has to be overwritten and my_table is a set (concurrency ?).

PC