Postgres: Action relationships¶

Step 0: Create an action¶

Create an action either from scratch or derived from an existing mutation.

Step 1: Open the action relationship section¶

• From your action, go to the Relationships tab.
• Click Add a relationship.

In this example, we’re creating a relationship for the createUser action.

Step 2: Define the relationship¶

The following values can be defined for an action relationship:

• Relationship type: Select a type of relationship.
  • Object relationship: For one-to-one relationships.
  • Array relationship: For one-to-many relationships.
• Relationship name: Create a name for the relationship.
• Reference schema: Select a reference schema from your database.
• Reference table: Select a table from your database.
• From: Select a field returned in the action response.
• To: Select a column from the reference table to join the field to.

Console

CLI

API

In the section opened by the above step, fill out the following fields:

You can add an action relationship by adding it to the respective custom type in the actions.yaml file inside the metadata directory:

- custom_types
  - objects
    - name: UserOutput
      relationships:
      - remote_table:
          schema: public
          name: users
        name: user
        type: object
        field_mapping:
          id: id

Apply the metadata by running:

hasura metadata apply

You can create an action relationship when defining custom types via the set_custom_types metadata API:

POST /v1/query HTTP/1.1
Content-Type: application/json
X-Hasura-Role: admin

{
  "type": "set_custom_types",
  "args": {
    "scalars": [],
    "enums": [],
    "input_objects": [],
    "objects": [
      {
        "name": "UserOutput",
        "fields": [
          {
            "name": "id",
            "type": "Int!"
          }
        ],
        "relationships": [
          {
            "name": "user",
            "type": "object",
            "remote_table": "users",
            "field_mapping": {
              "id": "id"
            }
          }
        ]
      }
    ]
  }
}

In this example, we’re creating a relationship called user, from the id field returned in the action response, to the id column of the users table.

Step 3: Explore with GraphiQL¶

In the GraphiQL tab, test out your action relationship.

mutation {
  createUser(name: "Hodor") {
    id
    user {
      name
      auth0_id
    }
  }
}

If your table has an existing remote relationship, you can also query the fields from the remote schema.

mutation {
  createUser(name: "Hodor") {
    id
    user {
      name
      auth0_id
      auth0_profile {
        email
        nickname
        last_login
      }
    }
  }
}

In the Postgres: Remote schema relationships section, we joined our users table with a remote Auth0 schema. Here, we’re able to get the Auth0 profile data of the user returned from our action.