Page updated Mar 13, 2024

Customize data model identifiers

Identifiers are defined using the .identifier() method on a model definition. Usage of the .identifier() method is optional; when it's not present, the model will automatically have a field called id of type ID that is automatically generated unless manually specified.

1const schema = a.schema({
2 Todo: a.model({
3 content: a.string(),
4 completed: a.boolean(),
5 }),
1const client = generateClient<Schema>();
3const todo = await client.models.Todo.create({ content: 'Buy Milk', completed: false });
4console.log(`New Todo created: ${}`); // New Todo created: 5DB6B4CC-CD41-49F5-9844-57C0AB506B69

If you want, you can use Amplify Data to define single-field and composite identifiers:

  • Single-field identifier with a consumer-provided value (type: id or string, and must be marked required)
  • Composite identifier with a set of consumer-provided values (type: id or string, and must be marked required)

Single-field identifier

If the default id identifier field needs to be customized, you can do so by passing the name of another field.

1const schema = a.schema({
2 Todo: a.model({
3 todoId:,
4 title: a.string(),
5 completed: a.boolean(),
6 }).identifier(['todoId'])
7 .authorization([a.allow.public()]),
10const client = generateClient<Schema>();
12 const { data: todo, errors } = await client.models.Todo.create({ todoId: 'MyUniqueTodoId', title: 'Buy Milk', completed: false });
13console.log(`New Todo created: ${todo.todoId}`); // New Todo created: MyUniqueTodoId

Composite identifier

For cases where items are uniquely identified by more than a single field, you can pass an array of the field names to the identifier() function:

1const schema = a.schema({
2 StoreBranch: a.model({
3 tenantId:,
4 name: a.string().required(),
5 country: a.string(),
6 state: a.string(),
7 city: a.string(),
8 zipCode: a.string(),
9 streetAddress: a.string(),
10 }).identifier(['tenantId', 'name'])
11 .authorization([a.allow.public()]),
14const client = generateClient<Schema>();
16const branch = await client.models.StoreBranch.get({ tenantId: '123', name: 'Downtown' }); // All identifier fields are required when retrieving an item