[API reference](https://evolu.dev/docs/api-reference) › [@evolu/common](https://evolu.dev/docs/api-reference/common) › [local‑first/Schema](https://evolu.dev/docs/api-reference/common/local-first/Schema) › RequiredColumnKeys

```ts
type RequiredColumnKeys<T> = {
  [K in keyof T]: null extends StandardSchemaV1.InferOutput<T[K]> ? never : K;
}[keyof T];
```

Defined in: [packages/common/src/local-first/Schema.ts:400](https://github.com/evoluhq/evolu/blob/49ea8ca499566aba270f8cb601e7f49aa62320f8/packages/common/src/local-first/Schema.ts#L400)