create

create defines the database schema and returns React Hooks. Evolu uses Schema (opens in a new tab) for domain modeling.

Example

import * as Schema from "@effect/schema/Schema";
import * as Evolu from "evolu";
 
const TodoId = Evolu.id("Todo");
type TodoId = Schema.To<typeof TodoId>;
 
const TodoTable = Schema.struct({
  id: TodoId,
  title: Evolu.NonEmptyString1000,
  isCompleted: Evolu.SqliteBoolean,
});
type TodoTable = Schema.To<typeof TodoTable>;
 
const Database = Schema.struct({
  todo: TodoTable,
});
 
export const {
  useQuery,
  useMutation,
  useEvoluError,
  useOwner,
  useOwnerActions,
} = Evolu.create(Database);

Tables and columns shall not be removed because there is a possibility that somebody is already using them. Column types shall be enriched only.

With this simple rule, any app version can handle any schema version. Evolu database is schemaless and doesn't have to be migrated when a schema is changed. Migrations are not feasible for local-first apps.

If an obsolete app gets a sync message with a newer schema, Evolu automatically updates the database schema to store the message safely, and useQuery filterMap helper will ignore unknown rows until the app is updated.

To learn more about migration-less schema evolving, check the useQuery documentation.