[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:151](https://github.com/evoluhq/evolu/blob/e7144e2bbe9069362b62dec1b64a8aa922b8f1b0/packages/common/src/Relation.ts#L151)

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:153](https://github.com/evoluhq/evolu/blob/e7144e2bbe9069362b62dec1b64a8aa922b8f1b0/packages/common/src/Relation.ts#L153)

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:156](https://github.com/evoluhq/evolu/blob/e7144e2bbe9069362b62dec1b64a8aa922b8f1b0/packages/common/src/Relation.ts#L156)

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