[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) › createRelation

## Call Signature

```ts
function createRelation<A, B>(): Relation<A, B>;
```

Defined in: [packages/common/src/Relation.ts:181](https://github.com/evoluhq/evolu/blob/dd96d79f1dbe9a49fa12ce8e0aa7d3d0177795ca/packages/common/src/Relation.ts#L181)

Creates a [Relation](https://evolu.dev/docs/api-reference/common/Relation/interfaces/Relation).

## Call Signature

```ts
function createRelation<A, B, LA, LB>(
  options: CreateRelationOptions<A, B, LA, LB>,
): Relation<A, B>;
```

Defined in: [packages/common/src/Relation.ts:184](https://github.com/evoluhq/evolu/blob/dd96d79f1dbe9a49fa12ce8e0aa7d3d0177795ca/packages/common/src/Relation.ts#L184)

Creates a [Relation](https://evolu.dev/docs/api-reference/common/Relation/interfaces/Relation) with custom logical key lookups.