Esteban A. Maringolo wrote > I think it is a tricky thing to do "in memory transactions", even > without thinking about databases. > You have to define what to keep and where to place the "original" > values (inst. vars.) of the object. > > As a general purpose solution if you can do that, you end up > implementing a mini gemstone in Pharo :) > > But what's sure is that you should have a mini object-table of the > "touched" objects or do "explicit" registration of these objects like > GLORP allows you to do. > > e.g. > > | p | > p := Person new. > System transaction: [:tx | > tx register: p. > p name: 'Nobody'. > p age: 70. > ].
It seems to me that the fundamental problem with the idea of registering each object with the transaction (or anything else) is that it requires white-box knowledge of what every invoked behaviour will do and touch. The above example is so minimal, it looks easy. I think if you really want transactional Smalltalk, you need to use one designed expressly for that purpose. (And fortunately, there is one.) > self assert: p name equals: 'Nobody'. > self assert: p age equals: 70. > > I'm using System here, to make it compatible with GemStone. > #transaction: could be implemented in terms of #beginTransaction, > #commitTransaction and internally use #abortTransaction if an > unhandled Error is signalled. > > Regards! > > Esteban A. Maringolo > El lun., 30 jul. 2018 a las 10:17, Peter Uhnák (< > i.uhnak@ > >) escribió: >> >> Hi, >> >> is there some library or approach how to do transactions in pharo? >> And I don't mean database transactions, but directly in memory on Pharo >> objects... e.g. >> >> p := Person new. >> >> transaction do: [ >> p name: 'Nobody'. >> p age: 70. >> ] on: Error do: [ >> transaction rollback. >> ]. >> >> self assert: p name equals: 'Nobody'. >> self assert: p age equals: 70. >> >> transaction do: [ >> p name: 'Somebody'. >> p age: 1 / 0. >> ] on: Error do: [ >> transaction rollback. >> ]. >> >> self assert: p name equals: 'Nobody'. >> self assert: p age equals: 70. >> >> Any pointers appreciated. >> >> Thanks, >> Peter -- Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html
