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Yurii Rashkovskii
@yrashk
(btw, es4j is not being abandoned yet — I am usign it in production :) but I do plan to move it over to PumpkinDB backend eventually)
Yurii Rashkovskii
@yrashk
(which means that es4j event/command models will still be usable)
Yurii Rashkovskii
@yrashk
Released the first version of the PumpkinDB backend! http://pumpkindb.org/
es-sameroom
@es-sameroom
[armetiz (armetiz_), irc.freenode.net] hi there
[armetiz (armetiz_), irc.freenode.net] I get a recurring problem using EventSourcing; and I'm wondering if I doing something wrong or If I'm missing pattern
[armetiz (armetiz_), irc.freenode.net] When our aggregate is dealing with a collection; ie: Booking is dealing with a collection of services (VO)
[armetiz (armetiz_), irc.freenode.net] A changed event can occurred; ie: BookingChanged
[armetiz (armetiz_), irc.freenode.net] The BookingChanged is contains the collection of services.
[armetiz (armetiz_), irc.freenode.net] Many time; I need to know the previous version of collection services to compute some differential; the differential can be useful to remove changed/deleted services from a Planning
[armetiz (armetiz_), irc.freenode.net] I can see two solution
[armetiz (armetiz_), irc.freenode.net] 1. Improve BookingChanged event with getServices; getAddedServices; getRemovedServices; getChangedServices;
[armetiz (armetiz_), irc.freenode.net] 2. Make a projection with services at version - 1
es-sameroom
@es-sameroom
[armetiz (armetiz_), irc.freenode.net] The 1. is very easy to handle.. But it's not very space efficient and I think it is not the "event-sourcing" state of art
[armetiz (armetiz_), irc.freenode.net] 2. is a good solution. But it add complexity in our read-model;
[armetiz (armetiz_), irc.freenode.net] Do you have any clue / experience about this topic ?
[armetiz (armetiz_), irc.freenode.net] thanks a lot ;)
es-sameroom
@es-sameroom
[armetiz (armetiz), irc.freenode.net] hi there
[armetiz (armetiz), irc.freenode.net] Let's imagine two kind of aggregate : TransportReservation & RoadMap.
[armetiz (armetiz), irc.freenode.net] A TransportReservation contains booked services from a customer; and an operator can assign some of them to a RoadMap.
[armetiz (armetiz), irc.freenode.net] I'm wondering if RoadMap aggregate should be updated using a Process when a TransportReservation is cancelled by customer; or if it's only a read-model concern
[armetiz (armetiz), irc.freenode.net] Our Product Owner are explicit : When a reservation is cancelled, every services should be removed from existing roadmap because our driver are not concerned about.
es-sameroom
@es-sameroom
[armetiz (armetiz), irc.freenode.net] In this circumstance; when a deletion occurred in every application I've made, I'm afraid to make a "relation-database system" .. Which is not really the purpose
[armetiz (armetiz), irc.freenode.net] Do you have any point of view ?
[armetiz (armetiz), irc.freenode.net] One argument could be "A RoadMap should not be composed of more than 10 services;" so the deletion information have to be transferred.
es-sameroom
@es-sameroom
[Daniel Basten (axhm3a), irc.freenode.net] does anyone have some experience with event sourcings frameworks? i am looking at akka persistence right now.
es-sameroom
@es-sameroom
[chat (chat_), irc.freenode.net] can you point me to good books or papers about event sourcing?
es-sameroom
@es-sameroom
[alex (ghostal), irc.freenode.net] trying to wrap my head around event sourcing. if i'm validating that a proposed change is valid, e.g. transfer $100 from account A to account B requires that account A has >= $100 in it, what do i validate against?
[alex (ghostal), irc.freenode.net] if i validate against application state/database, that's not the single source of truth. if the single source of truth is the event sequence, does that mean i have to run through the entire event sequence every time i want to validate something?
[alex (ghostal), irc.freenode.net] if, say, i validate against the database, as a "projection" of the truth, but there's a bug in how i'm maintaining that database, then i subsequently put an invalid event onto the sequence... what happens then?
es-sameroom
@es-sameroom
[purple (aimag), irc.freenode.net] Hi everyone
[purple (aimag), irc.freenode.net] I want to implement event sourcing. My question is when a command is not valide or can not be performed in the system the better solution is always store the event of this one or not in event store. And if we store it, after that we must run a evolution function or?
Mihail Malo
@qm3ster
OH NO THERE'S AN IRC IN HERE WE ARE ALL GONNA DIE