event-sourcing

问题 In CQRS / ES based systems, you store events in an event-store. These events refer to an aggregate, and they have an order with respect to the aggregate they belong to. Furthermore, aggregates are consistency / transactional boundaries, which means that any transactional guarantees are only given on a per-aggregate level. Now, supposed I have a read model which consumes events from multiple aggregates (which is perfectly fine, AFAIK). To be able to replay the read model in a deterministic way

问题 In CQRS / ES based systems, you store events in an event-store. These events refer to an aggregate, and they have an order with respect to the aggregate they belong to. Furthermore, aggregates are consistency / transactional boundaries, which means that any transactional guarantees are only given on a per-aggregate level. Now, supposed I have a read model which consumes events from multiple aggregates (which is perfectly fine, AFAIK). To be able to replay the read model in a deterministic way

问题 In CQRS / ES based systems, you store events in an event-store. These events refer to an aggregate, and they have an order with respect to the aggregate they belong to. Furthermore, aggregates are consistency / transactional boundaries, which means that any transactional guarantees are only given on a per-aggregate level. Now, supposed I have a read model which consumes events from multiple aggregates (which is perfectly fine, AFAIK). To be able to replay the read model in a deterministic way

问题 I implement Event Sourcing and CQRS pattern in my application. I inspired by CQRS journey where I downloaded sample code. There I found whole infrastructure for Event sourcing (CommandHandlers, EventHandlers, Events, Envelopes ... etc.), but it is quite big amount of code and I can't imagine that I need all of code for my simple Event sourcing. Do you know some common tested library/nuget package/project containing all infrastructure for sending/registering commands, events and everything

问题 I'm working on my first 'real' Haskell project, and simultaneously trying to get my head around event sourcing. (It seemed like a good match; event sourcing is a rather functional way of looking at data.) I've hit a wall trying to figure out how to deserialise my events into strongly typed Haskell data. There are two opposing forces at work here: It shouldn't be possible to apply an event to the wrong type of aggregate. This requirement suggests that I need a separate type of event for each

问题 How can I access all stored events in the EventStore to rebuild my read models? A method called GetFrom is mentioned at question J Oliver EventStore V2.0 questions, but I cannot find this method on the interface "IStoreEvents" which is returned from Wireup. 回答1: That method is a part of the IPersistStreams interface and not the IStoreEvents interface. The API needs to be refined slightly to accommodate that. I have just added a method to IStoreEvents called GetFrom(DateTime started) that

问题 I am trying to learn more about CQRS and Event Sourcing (Event Store). My understanding is that a message queue/bus is not normally used in this scenario - a message bus can be used to facilitate communication between Microservices, however it is not typically used specifically for CQRS. However, the way I see it at the moment - a message bus would be very useful guaranteeing that the read model is eventually in sync hence eventual consistency e.g. when the server hosting the read model

问题 I'm trying to wrap my head around transactions in event sourcing. I have one aggregate (transaction scope) in my event store. A command gets processed and is producing 10 events. Now, can this be handled as 1 transaction or is this 10 transactions? With transaction I mean changes to the state that is only valid together as a whole. Have I designed my events wrong if they are split up into many events like this even though I want them to be handled as a whole? I tend to think that it is the

问题 EventSourcing works perfectly when we have particular unique EntityID but when I am trying to get information from eventStore other than particular EntityId i am having tough time. I am using CQRS with EventSourcing. As part of event-sourcing we are storing the events in SQL table as columns(EntityID (uniqueKey),EventType,EventObject(eg. UserAdded)). So while storing EventObject we are just serializing the DotNet object and storing it in SQL, So, All the details related to UserAdded event

问题 EventSourcing works perfectly when we have particular unique EntityID but when I am trying to get information from eventStore other than particular EntityId i am having tough time. I am using CQRS with EventSourcing. As part of event-sourcing we are storing the events in SQL table as columns(EntityID (uniqueKey),EventType,EventObject(eg. UserAdded)). So while storing EventObject we are just serializing the DotNet object and storing it in SQL, So, All the details related to UserAdded event