Gen 1 to Gen 2 Migration - Schema Usage

[sajithkumarsb]

Amplify CLI Version

v12.13.1

Question

I want to migrate my Gen 1 app to a Gen 2 app, and I wish to reuse my existing Gen 1 GraphQL Schema (SDL) in Gen 2 . My Gen 1 schema includes features such as @model queries, mutations, subscriptions, directives like @hasone, @hasmany, and @belongsTo on required fields, as well as many-to-many relationships. However, according to the Gen 2 documentation and the Gen 1 vs. Gen 2 feature matrix, these features are not supported in Gen 2.

My questions are:
Is there any way to combine both Gen 1 and Gen 2 schemas to make them usable in Gen 2?
What alternative approaches are available to implement the above features in Gen 2?

Documents referred :
Gen 1 schema support: https://docs.amplify.aws/react/build-a-backend/data/data-modeling/#gen-1-schema-support
Gen 1 vs. Gen 2 feature matrix : https://docs.amplify.aws/react/start/migrate-to-gen2/#gen-1-vs-gen-2-feature-matrix

[dpilch]

1. It is not possible to combine a string SDL schema and schema from the data schema builder at this time. If you use only a string SDL schema (as you linked here) you will be able to use the unsupported Gen 1 features in your Gen 2 app (it will just print a warning until the next major version release). At this time I would recommend that you modify your schema in your Gen 1 app to be compatible with your Gen 2 app.
2. Required relational fields will not be possible in Gen 2. For many to many relationship you will need to create a join model https://docs.amplify.aws/react/build-a-backend/data/data-modeling/relationships/#model-a-many-to-many-relationship.

However, if you recreate your app in Gen 2 your data will not be copied over automatically and you will need to implement your own replication if you go this route.

We are planning to release official migration support in the future that will replicate your data in the Gen 2 app automatically.

[sajithkumarsb]

1. It is not possible to combine a string SDL schema and schema from the data schema builder at this time. If you use only a string SDL schema (as you linked here) you will be able to use the unsupported Gen 1 features in your Gen 2 app (it will just print a warning until the next major version release). At this time I would recommend that you modify your schema in your Gen 1 app to be compatible with your Gen 2 app.
2. Required relational fields will not be possible in Gen 2. For many to many relationship you will need to create a join model https://docs.amplify.aws/react/build-a-backend/data/data-modeling/relationships/#model-a-many-to-many-relationship.

However, if you recreate your app in Gen 2 your data will not be copied over automatically and you will need to implement your own replication if you go this route.

We are planning to release official migration support in the future that will replicate your data in the Gen 2 app automatically.

Thank you for the clarfication. I also want to know about the filed level querying in gen 2.

Example :

I have a model Tenant in gen 1 with the field logoImage how to achieve this in gen 2.

type Tenant
@model(subscriptions: null, mutations: {create: null}
logoImage: ImageUploadS3Object
@function(name: "MainCoreResolvers-${env}")
@auth(rules: [{ allow: groups, groupsField: "id" }])
}

What i have done in gen 2  (In this getting a typescript error )

Tenant: a.model({
logoImage: a.query(a.ref(ImageUploadS3Object))..authorization((allow) => 

[allow.groupDefinedIn("id")])).handler(a.handler.custom({ entry: "../resolvers/tenant/logo-image.ts", dataSource:
a.ref("ImageUploadS3Object") })), })

ImageUploadS3Object: a.customType({ url: a.string(), uploadUrl: a.url() })