[API reference](https://evolu.dev/docs/api-reference) › [@evolu/common](https://evolu.dev/docs/api-reference/common) › [Relation](https://evolu.dev/docs/api-reference/common/Relation) › CreateRelationOptions

Defined in: [packages/common/src/Relation.ts:172](https://github.com/evoluhq/evolu/blob/037c390af081e9944d616ff298a729515c5c5ab7/packages/common/src/Relation.ts#L172)

Options for [createRelation](https://evolu.dev/docs/api-reference/common/Relation/functions/createRelation).

## Properties

<a id="lookupa"></a>

### lookupA?

```ts
readonly optional lookupA?: Lookup<A, LA>;
```

Defined in: [packages/common/src/Relation.ts:174](https://github.com/evoluhq/evolu/blob/037c390af081e9944d616ff298a729515c5c5ab7/packages/common/src/Relation.ts#L174)

Derives logical identity for A values. Defaults to [identity](https://evolu.dev/docs/api-reference/common/Function/functions/identity).

---

<a id="lookupb"></a>

### lookupB?

```ts
readonly optional lookupB?: Lookup<B, LB>;
```

Defined in: [packages/common/src/Relation.ts:177](https://github.com/evoluhq/evolu/blob/037c390af081e9944d616ff298a729515c5c5ab7/packages/common/src/Relation.ts#L177)

Derives logical identity for B values. Defaults to [identity](https://evolu.dev/docs/api-reference/common/Function/functions/identity).