CODEWITHSUNDEEP
databaseazuredata-structuresazure-cosmosdbazure-cosmosdb-sqlapi
bnm12
bnm12

Reputation: 83

How to structure many-to-many relationships in cosmos db

I'm working on a new project and it was recommended to me that I have a look at Cosmos DB to use for my data store for it because it's going to be a global SaaS application servicing potentially hundreds of thousands of users.

As this is my first foray into NoSQL databases I've inevitably run into a lot of things I have to learn but I feel like I've been slowly getting it and have actually become quite excited about it.

Now here comes the kicker: I have a relatively simple data structure that I just can't seem to wrap my head around how you'd implement and I've pretty much resigned to the fact that it might just be a workload which doesn't really work well in non-relational databases. But as I said I'm completely green so I'm here for a sanity check in case there's something obvious that I'm missing

I have a data structure consisting of a "user" object and a "post" object and I need to relate them based on unbounded arrays of tags to basically create customized feeds they look like this

User:

{
    id: 1,
    name: "username",
    interests: [
        "fishing",
        "photography",
        "stargazing",
    ]
}

Post:

{
    id: 1,
    title: "My post title",
    body: "My post content",
    tags: [
        "tennis",
        "sport",
        "photography",
    ]
}

I want to return a list of all posts which has one or more of a given users interests in their tags so basically a query like this:

SELECT DISTINCT VALUE Posts FROM Posts
JOIN tag IN Posts.Tags
WHERE tag IN <<user.interests>>

In SQL I'd create a table of users and a table of posts and join them based on shared tags/interests but I can't for the life of me figure out how to denormalize this (if possible). Have I really run into one of the impossible flows of NoSQL on my first attempt with only 2 objects? Or am I just being a total noob?

Upvotes: 7

Views: 5395

Answers (1)

Mark Brown
Mark Brown

Reputation: 8763

You're on the right track! There are two really good articles that describe how to model data for NoSQL. Definitely worth a read if you're new to this type of data store.

Data modeling in Azure Cosmos DB, in particular the section on many-to-many relationships.

and

How to model and partition data on Azure Cosmos DB using a real-world example

Hope you find this helpful.

Upvotes: 6

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