old and new value shows the same

[abbielara20]

I am using the git repository and following the Use Case 1: Trace the changes of child nodes from the current entity and display the meaningful data from child nodes (composition relation). However, the new value and old value registers the same.

change-tracking.cds
using { ProcessorService } from './processor-service';

annotate ProcessorService.Incidents with @changelog: [title] {
conversation @changelog: [conversation.message];
customer @changelog: [customer.email];
}

schema.cds
entity Incidents : cuid, managed {
customer : Association to Customers;
title : String @title: 'Title';
urgency : Association to Urgency default 'M';
status : Association to Status default 'N';
conversation : Composition of many Conversation;
}
aspect Conversation: managed, cuid {
timestamp : type of managed:createdAt;
author : type of managed:createdBy;
message : String;
};

[Sv7enNowitzki]

Hi @abbielara20 ,

It seems that this use case lacks some explanation. As I understand it, in this use case (where a parent entity nests annotated child entities), the plugin only supports changelogs generated by the creation and deletion of conversation entities. When it comes to updates, there can be significant performance issues in a composition relationship from the parent entity to the child entity. Therefore, updates are not supported here and should not generate a changelog.

So when you don't need to track the deep changes, but still want to track the additions and removals in the composition, you can set it up as described above. At this point, updates to Conversations should not generate a changelog.

As for why an update changelog was generated here, this might be a bug that needs to be discussed and resolved to prevent changelogs from being generated in such cases.

Additionally, in a composition relationship, if you want to record the change history of a conversation entity, please directly add annotations in the conversation as shown below:

annotate Incidents.conversation with {
  message  @changelog;
}

Best Regards,
Wenjun

[abbielara20]

Just to confirm, I believe this only works with aspects? I tried the code by changing the conversations to an entity but it is not being recognized in the annotation.

[Sv7enNowitzki]

Just to confirm, I believe this only works with aspects? I tried the code by changing the conversations to an entity but it is not being recognized in the annotation.

No, "aspect" is not the only one that can take effect. How did you do it?

[abbielara20]

No, "aspect" is not the only one that can take effect. How did you do it?

I changed the conversation to an entity and followed the same Incidents.conversation. But it gets artifact conversation not found. Although, there is no issue if it's an aspect.

entity Incidents : cuid, managed {
  customer       : Association to Customers;
  title          : String @title: 'Title';
  urgency        : Association to Urgency default 'M';
  status         : Association to Status default 'N';
  conversation   : Composition of many Conversations on conversation.ID = $self.ID;
}

entity Conversations: managed, cuid {
    timestamp : type of managed:createdAt;
    author    : type of managed:createdBy;
    message   : String;
  };

annotate ProcessorService.Incidents {
  customer @changelog: [customer.name];
  title    @changelog;
  status   @changelog;
}

annotate ProcessorService.Incidents.conversation with @changelog: [author, timestamp] {
    message  @changelog @Common.Label: 'Message';
}

[Sv7enNowitzki]

No, "aspect" is not the only one that can take effect. How did you do it?

I changed the conversation to an entity and followed the same Incidents.conversation. But it gets artifact conversation not found. Although, there is no issue if it's an aspect.

entity Incidents : cuid, managed {
  customer       : Association to Customers;
  title          : String @title: 'Title';
  urgency        : Association to Urgency default 'M';
  status         : Association to Status default 'N';
  conversation   : Composition of many Conversations on conversation.ID = $self.ID;
}

entity Conversations: managed, cuid {
    timestamp : type of managed:createdAt;
    author    : type of managed:createdBy;
    message   : String;
  };

annotate ProcessorService.Incidents {
  customer @changelog: [customer.name];
  title    @changelog;
  status   @changelog;
}

annotate ProcessorService.Incidents.conversation with @changelog: [author, timestamp] {
    message  @changelog @Common.Label: 'Message';
}

If you want to set Conversations as entity, then you also need to set your cds model as below:

entity Incidents : cuid, managed {
  ...
  conversation : Composition of many Conversation
                   on conversation.up_ = $self;
}

entity Conversation : managed, cuid {
  ...
  up_       : Association to Incidents;
};

And set @changelog as below:

annotate ProcessorService.Conversation with @changelog: [author, timestamp] {
  message  @changelog;
}

If you add @changelog in the following manner, theoretically, there should be no changelog generated for update operations, as I've already mentioned in my previous comment:

annotate ProcessorService.Incidents with @changelog: [title] {
  conversation @changelog: [conversation.message];
}