I also had this problem and it took my some time to realize that this is an issue by design. When you say Post.comments
then you refer to the relationship that says "these are all the comments of that post". However, now you want to filter them. If you'd now specify that condition somewhere on subqueryload
then you are essentially loading only a subset of values into Post.comments
. Thus, there will be values missing. Essentially you have a faulty representation of your data in the model.
The question here is how to approach this then, because you obviously need this value somewhere. The way I go is building the subquery myself and then specify special conditions there. That means you get two objects back: The list of posts and the list of comments. That is not a pretty solution, but at least it is not displaying data in a wrong way. If you were to access Post.comments
for some reason, you can safely assume it contains all posts.
But there is room for improvement: You might want to have this attached to your class so you don't carry around two variables. The easy way might be to define a second relationship, e.g. published_comments
which specifies extra parameters. You could then also control that no-one writes to it, e.g. with attribute events. In these events you could, instead of forbidding manipulation, handle how manipulation is allowed. The only problem might be when updates happen, e.g. when you add a comment to Post.comments
then published_comments
won't be updated automatically because they are not aware of each other. Again, I'd take events for this if this is a required feature (but with the above ugly solution you would not have that either).
As a last, hybrid, solution you could take the first approach and then just assign those values to your object, e.g. Post.deleted_comments = deleted_comments
.
The thing to keep in mind here is that it is generally not a clever idea to manipulate the query the ORM makes as this could lead to problems later on. I have taken this approach and manipulated the queries (with contains_eager
this is easily possible) but it has created problems on some points (while generally being functional) so I dropped that approach.