CODEWITHSUNDEEP
parse-platform
giacavicchioli
giacavicchioli

Reputation: 334

Parse.com post-comment relationship

I would like to build a application like facebook (actually has nothing to do with facebook, but for the nature of the question we can say so).
I currently have a table named Post and another named Comment and of course I would represent the one-to-many relationship between them (I read the documentation here but wasn't really helpful to me).

In Comment I created a column with a pointer to the Post class with the parent Post.
In Post I created then a column with an Array where will be stored the related comment's id.
(each post will have a number of comments not very high, between 10 and 100).

The technique used here is the best? There are more efficient methods?

Upvotes: 0

Views: 312

Answers (1)

rickerbh
rickerbh

Reputation: 9913

If your array is only storing the objectIDs for the comments then it's probably more idiomatic to use a Relation as the column type rather than an Array.

A Relation is more efficient in that the ID's aren't returned when you retrieve your Post object, so your Post objects will transfer faster, and it has the same disadvantages as storing the object ID's in an Array in that you'll still have to run a query to get the Comment objects. The only possible downside I can see is that if you need to have the number of comments, you can calculate this based on the size of the array, but with a Relation you'll have to run a count query (or maintain a separate count field).

With an Array you're introducing a slight data maintenance/integrity overhead as well. If your users have the ability to delete comments, then you'll also need to remove the comment ID from the array. And this will require a permissive ACL (to allow a commenter to edit a post they may not have created, and because of this they'll have the ability to edit any value in the post), or you'll have to have a before/after save action to update the Post when a Comment is deleted.

Upvotes: 1

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