# Directus Basics Part 2 — Understanding Relationships (M2O, O2M, M2M)

%[https://www.youtube.com/watch?v=7SNrBzaxreg&t=10s] 

This is part two of our Directus Basics series. In [part one](https://www.youtube.com/watch?v=tJGuxqhv2SY&t=11s), we set up a Directus instance and created our first collection. Today we're covering one of the most powerful features Directus offers: **relationships** between collections.

By the end of this article, you'll understand three core relationship types — Many to One (M2O), One to Many (O2M), and Many to Many (M2M). There's a fourth type, Many to Any (M2A), which we'll cover in a future post.

## Setting Up the Branding Collection

Continuing from our existing Directus instance, let's create a new collection called **branding**. Select all the additional default fields Directus offers.

Add two fields:

| Field | Type |
| --- | --- |
| `name` | String (basic input) |
| `description` | Text (textarea) |

Once the collection is set up, add a few entries — I'd recommend at least two different brands so you can see the relationship in action once it's wired up.

## Many to One (M2O): Products → Branding

Head over to your **products** collection. We want to connect a product to a brand.

Logically: many products can belong to *one* brand. That's a Many to One relationship — many products, to one brand.

Steps:

1.  Create Field → Relational category → **Many to One**
    
2.  Key: `brand_id`
    
3.  Related Collection: `branding`
    
4.  De-select **Enable Create Button** — you always want to choose a brand from an existing list, not create one on the fly
    
5.  Save
    

## One to Many (O2M): Branding → Products

Since one brand can have *many* products, we need to set up the reverse relationship explicitly on the **branding** collection.

Steps:

1.  Create Field → Relational category → **One to Many**
    
2.  Key: `products`
    
3.  Related Collection: `products`
    
4.  Foreign Key: `brand_id` — the field we just created on the products side
    
5.  De-select **Enable Create Button**
    
6.  Save
    

## Seeing the Relationship in Action

Go back into your **products** collection and assign a brand to each product. Make sure at least two products share the same brand so the relationship is visible.

You'll notice each product can only belong to **one** brand — that's the M2O relationship at work.

Now open the **branding** collection and click into one of your brands. You'll see the products you just assigned show up automatically — you didn't have to add them manually. Directus handled that because of the relationship you configured.

## Many to Many (M2M): Products ↔ Tags

M2M relationships work differently — both sides can have many related records.

A common real-world example: **tags** on products, used to improve SEO. A single product can have multiple tags, and a single tag can apply to many products.

### Create the Tags Collection

Create a new collection called **tags**, with the same two fields as before:

| Field | Type |
| --- | --- |
| `name` | String |
| `description` | Text (textarea) |

Add three or four tags before moving on.

### Wire Up the M2M Relationship

Back in the **products** collection:

1.  Create Field → Relational category → **Many to Many**
    
2.  Key: `tags`
    
3.  Related Collection: `tags`
    
4.  De-select **Enable Create Button**
    
5.  **Do not save yet** — scroll down and click **"Continue in Advanced Field Creation Mode"**
    
6.  In the sidebar, click **Relationship**, then find **Corresponding Field**
    
7.  Check **"Create Field"** — under Field Name, you should see `products` appear
    
8.  Save
    

> **Why the advanced flow?** Under Corresponding Field, `products` appears automatically — that's Directus telling you it's about to create the matching relational field back on the **tags** collection. Unlike the M2O/O2M setup, you don't have to manually configure both sides — Directus builds the reverse relationship for you.

Now, when you add a tag to a product, Directus automatically links that product under the corresponding tag in the **tags** collection — no manual syncing required.

## Summary

| Relationship | Direction | Example |
| --- | --- | --- |
| M2O | Many records → one related record | Products → Branding |
| O2M | One record → many related records | Branding → Products |
| M2M | Many ↔ many, both directions | Products ↔ Tags |

Relationships are one of those Directus features that make a lot more sense once you've built one yourself than they do reading about them — so I'd recommend replicating this setup in your own instance before moving on.

That wraps up part two. In part three, we'll cover Directus **permissions** — how to control exactly who can see and edit your data.

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*Found this useful? Follow for more Directus and TanStack Start tutorials, or check out the video version on* [*YouTube*](https://www.youtube.com/watch?v=7SNrBzaxreg&t=11s)*.*