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Building a GraphQL Endpoint with Deno

Updating our Schema

Explore how to update your MongoDB schema for Book, Author, and Review collections while managing relationships via authorId and reviewIds. Learn to define detailed GraphQL queries and mutations, implement resolvers with TypeScript using MongoDB driver methods, and test your GraphQL endpoint integrated with MongoDB in a Deno application.

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
...