CODEWITHSUNDEEP
javascriptmongodbmongoosemongoose-populate
Xavier Le Tohic
Xavier Le Tohic

Reputation: 3

Finding a referenced document in all the existing collection using Mongoose

I have 3 collections :

events :

{
   _id: ObjectId(54ca0f2506d0c6b673b2fde8),
   _reference: ObjectId("54fd786c549e96f70f9c027d")
},
{
   _id: ObjectId(54acd81941a646d768922cfa),
   _reference: ObjectId("54fd786c549e96f70f9c027d")
}

posts : 

{
   _id: ObjectId(54fd786c549e96f70f9c027d),
   title: "This is a post",
   content: "This is the content of the post"
}

comments :

{
   _id: ObjectId(54fd786c549e96f70f9c027e),
   content: "This is a comment on a post"
}

When a post or a comment is created, a document is also created in the collection "events" with a property called "_reference". This "_reference" will hold the ObjectId of the comment or post.

Then i need to recover all the documents (saved in the other collections ; i.e posts and comments) thats referenced in each document in the collection "events".

i used the populate method but that only allows me to check in ONE collection when I need to check in ALL the existing collections.

Bellow is an example of how I defined the reference property in the mongoose model :

_reference: {type: Schema.Types.ObjectId, ref: 'posts'}

Thanks in advance !

Upvotes: 0

Views: 63

Answers (1)

ncabral
ncabral

Reputation: 2522

You cannot define the schema of events like: 

_reference: {type: Schema.Types.ObjectId, ref: 'posts'}

and expect it to refer to comments as well. Because you're telling explicitly that the reference is for posts.

A better approach would be to save an ObjectID in events for the object you want to save, add a field called type where you would say if it's a comment or a post, and according to that, look up the designated collection for the ObjectId.

Upvotes: 1

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