> For the complete documentation index, see [llms.txt](https://docs.checkpoint.snapshot.box/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.checkpoint.snapshot.box/guides/one-to-one-relations.md).

# One-to-one relations

It's possible to create one-to-one relations in schema. Those relations will be then available for querying via GraphQL.

### Define relations in schema

To define one-to-one relation nested entity must have `id` field that is either `String!` or `ID!`. In parent entity create field (with any name) that is of nested entity's type (can be nullable or required).

```graphql
type Space {
  id: String!
  name: String
}

type Proposal {
  id: String!
  name: String
  space: Space!
}
```

### Create entities in writer 

When creating entities in writer set `Proposal`'s `space` field to the value of `Space`'s `id` field.

```typescript
const proposal = new Proposal('proposal_id');
proposal.name = 'Proposal name';
proposal.space = 'Space_id';

await proposal.save();
```

### Query data via GraphQL

It's now possible to nest space entity when querying proposals. You can still filter proposals by space (limited to `Space`'s `id` currently).

```graphql
{
  proposals(first: 10, where: { space: "0x00b60f2a154b9aaec8e4bec8e04f86d6cd92a9c993871e904bd815962603492d" }) {
    id
    space {
      id
      name
    }
  }
}
```


---

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