Building a GraphQL Endpoint with Deno/

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Updating our Schema

Updating our Schema

Learn how to update a schema by using MongoDB with an endpoint.

We'll cover the following...

Schema types and inputs

Our MongoDB database has three entities: Book, Author, and Review. Let’s consider the following schema:

C++
const types = gql`
    type Book {
        _id: String
        title: String
        price: Float
        identifier: String
        description: String
        author: Author
        reviews: [Review]
    }
    type SimpleBook {
        _id: String
        title: String
        price: Float
        identifier: String
        description: String
    }
    type Author {
        _id: String
        firstName: String
        lastName: String
    }
    type Review {
        _id: String
        bookId: String
        rating: Int
        comment: String
    }
`;

MongoDB schema

To access our database, we will need to define our schema as follows (they can be different from the GrapghQL ones):

TypeScript 3.3.4
// Defining schema interface
interface BookSchema {
    _id: Bson.ObjectId;
    title: string;
    price: number;
    identifier: string;
    description: string;
    authorId: Bson.ObjectId;
    reviewIds: Bson.ObjectId[];
}
interface AuthorSchema {
    _id: Bson.ObjectId;
    firstName: string;
    lastName: string;
}
interface ReviewSchema {
    _id: Bson.ObjectId;
    rating: number;
    comment: string;
    bookId: string;
}

In the schema definition given above, we try to use different approaches when handling the relationship between entities. It’s important to note the following:

  • authorId is a field in the book schema used to reference the author of the book.
  • reviewIds is an array of review
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