> For the complete documentation index, see [llms.txt](https://docs.cortex.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.cortex.io/ingesting-data-into-cortex/entities-overview/entities/defining-relationship-types.md).

# Defining relationship types

Every organization has structure: teams own services, services depend on each other, domains group related capabilities. Relationship types are how Cortex models that structure, letting you define not just *that* two entities are related, but *how* they relate and *what kinds* of entities can participate.

## Understanding relationship types in Cortex

A relationship type captures the semantics of a connection between entities: its directionality, the roles each side plays, and the constraints on what can appear at either end. Rather than treating all relationships as equivalent links, Cortex distinguishes between a few fundamentally different relationship patterns:

* **Entity relationships** - Customizable relationships (hierarchical or cyclical) between any entity types
* **Team hierarchies** - Hierarchical relationships specifically between teams, including [ownership](/ingesting-data-into-cortex/entities-overview/entities/ownership.md) over other entities. Learn more in [Understanding hierarchies](/ingesting-data-into-cortex/entities-overview/entities/adding-entities/teams/viewing-teams.md#understanding-hierarchies).
* **Domain hierarchies** - Hierarchical relationships between domains, with optional inheritance so ownership can flow down from parent to child. Learn more in [Viewing the domain hierarchy](/ingesting-data-into-cortex/entities-overview/entities/adding-entities/domains.md#viewing-the-domain-hierarchy).
* **Dependencies** - Cyclical relationships between non-team entities. Learn more in [Defining dependencies](/ingesting-data-into-cortex/entities-overview/entities/adding-entities/dependencies.md).

{% hint style="info" %}
Want to learn more? Check out the Cortex Academy course on [Catalogs, Entities, and Relationships](https://academy.cortex.io/courses/understanding-understanding-catalogs-entities-and-relationships).
{% endhint %}

### **Relationship direction: Source vs. destination**

Every relationship has a direction. The **source** is the parent (the upstream entity), and the **destination** is the child (the downstream entity). For example, in a *Repository* relationship, a `Service` (source/parent) contains a `Repository` (destination/child).

This direction determines how the relationship is drawn in an entity's relationships graph, so define it carefully when creating a relationship type. If upstream and downstream appear reversed, the source and destination entities were likely defined in the opposite order.

### Custom relationship type use cases

<table><thead><tr><th width="162.05206298828125">Relationship type</th><th width="255.739501953125">Description</th><th width="144.203125">Source</th><th>Destination</th></tr></thead><tbody><tr><td><strong>Repository</strong></td><td>Mapping services to repositories to view the hierarchy of repos and the services they contain. For example, a service is linked to its code repository.</td><td>Service</td><td>Repository</td></tr><tr><td><strong>Cloud account to resource</strong></td><td>Associating cloud accounts (like AWS, Google Cloud Project, or Azure subscription) with their respective resources (such as EC2 instances or other cloud resources).</td><td><ul><li>AWS account</li><li>GCP</li><li>Azure subscription</li></ul></td><td><ul><li>AWS resources (e.g., EC2)</li><li>Google Cloud resources</li><li>Azure resources</li></ul></td></tr><tr><td><strong>Service to environment</strong></td><td>Linking services to their deployment environments.</td><td>Service</td><td>Environment</td></tr><tr><td><strong>Monorepo</strong></td><td>Mapping multiple services to a single repository.</td><td>Repository</td><td>Service</td></tr><tr><td><strong>Service to endpoint</strong></td><td>Associating services with their endpoints.</td><td>Service</td><td>Endpoint</td></tr><tr><td><strong>Data center modeling</strong></td><td>Representing data centers and their relationships to other infrastructure components.</td><td>Data center</td><td>Component</td></tr></tbody></table>

{% hint style="warning" %}
Use team [ownership](/ingesting-data-into-cortex/entities-overview/entities/ownership.md) to represent ownership relationships, not custom relationship types.
{% endhint %}

## Viewing relationship types

### Viewing all configured relationship types

1. From the main sidebar, expand **Catalogs**, then select **All entities**.
2. Select the **Relationship types** tab.<br>

   <div align="left" data-with-frame="true"><figure><img src="/files/OOyl3qM4moPcJC0Yop00" alt="The &#x27;Relationship types&#x27; tab on the Entities page." width="375"><figcaption></figcaption></figure></div>
3. Select a relationship type from the list to view more information.

### Viewing relationships on entity pages

If an entity belongs to a relationship, you can explore that context directly from its [entity details page](/ingesting-data-into-cortex/entities-overview/entities/details.md).

1. Navigate to the entity's details page.
2. From the left entity details sidebar, select **Relationships**. Relationship types associated with the entity appear in the relationships graph.

In the example below, the entity `California` belongs to a relationship called `Geography` . Relationships default to **graph view**, giving you a visual map of parent/child connections, where sources (parents/upstream) connect to their destinations (children/downstream).

<div align="left" data-with-frame="true"><figure><img src="/files/ylRCehi5PuTKkXaF4EPA" alt="The relationship graph of an entity." width="563"><figcaption></figcaption></figure></div>

From the graph, click any entity to view a quick summary of its metadata. Select **Go to entity** to navigate directly to that entity's detail page.

<div align="left" data-with-frame="true"><figure><img src="/files/YEz3oeunR66kxlHX8nuJ" alt="" width="563"><figcaption></figcaption></figure></div>

Select **Table view** to see the same data in a structured list. This view is useful for quickly scanning or sorting related entities.

<div align="left" data-with-frame="true"><figure><img src="/files/yXZCT08HLJ34fQqs0TRv" alt="" width="563"><figcaption></figcaption></figure></div>

## Entity relationship CQL

You can create Scorecard rules and write [CQL queries](/standardize/cql.md) based on entity relationships. See more examples in the [CQL Explorer](https://app.getcortexapp.com/admin/cql-explorer) in Cortex.

<details>

<summary>Entity relationship destinations</summary>

All recursive destinations an entity for a relationship type, with an optional depth parameter to expand results

**Definition -** `entity.destinations(relationshipType = "my-relationship")`

**Examples**

You could write a Scorecard rule to ensure that an entity has at least one destination with the "my-relationship" type:

```
entity.destinations(relationshipType = "my-relationship").length > 0
```

</details>

<details>

<summary>Entity relationship sources</summary>

All recursive sources an entity for a relationship type, with an optional depth parameter to expand results

**Definition -** `entity.sources(relationshipType = "my-relationship")`

**Examples**

You could write a Scorecard rule that ensures an entity has at least one source with the "my-relationship" type:

```
entity.sources(relationshipType = "my-relationship").length > 0
```

</details>