graphql/graphcool: How to write a mutation that links both a one:one and a one:many relationship

问题

I have a schema as follows:

type Artist @model {
  id: ID! @isUnique
  createdAt: DateTime!
  updatedAt: DateTime!
  name: String! @isUnique
  songkickId: String
  shows: [Show!]! @relation(name: "ArtistShow")
}

type Show @model {
  id: ID! @isUnique
  createdAt: DateTime!
  updatedAt: DateTime!
  name: String
  songkickId: String
  date: DateTime! 
  soldOut: Boolean!
  pit: Boolean!
  ages: String!
  price: String!
  multiDay: Boolean!
  artists: [Artist!]! @relation(name: "ArtistShow")
  venue: Venue! @relation(name: "ShowVenue")
}

type Venue @model {
  id: ID! @isUnique
  createdAt: DateTime!
  updatedAt: DateTime!
  name: String! @isUnique
  address: String
  latitude: Float
  longitude: Float
  metro: String
  songkickId: String @isUnique
  shows: [Show!]! @relation(name: "ShowVenue")
}

I have written mutations that, given JSON data, create Artists and Venues and return those to me.

At the time that I want to create a Show, I have:

1. An array of Artist IDs
2. An ID for a Venue
3. All required info to populate the rest of the Show data (in an object called showInfo)

I have a mutation that looks like this:

        mutation: gql`
            mutation {
                createShow(
                    date: "${showInfo.date}"
                    soldOut: ${showInfo.soldOut}
                    pit: ${showInfo.pit}
                    ages: "${showInfo.ages}"
                    price: "${showInfo.price}"
                    multiDay: ${showInfo.multiDay}
                ) {
                    id
                }
            }
        `,

How do I edit this so that I also create relations between a Show that I am creating and appropriate Venue and Artist IDs?

回答1:

I had to structure the JSON so that I had access to a list of Artists and a Venue at the time that I was writing a Show.

I then had to write each Artist and Venue (or validate whether these had already been written) to graphcool and get a respective ID back.

I then executed a function like the following:

async findShowOrCreate (showInfo, artists, venue) {
        const tempDate = new Date(showInfo.date);
        this.logger.info(`BEGIN : write show to graphcool (${showInfo.venue} on ${tempDate.toDateString()})`);

        const showQuery =   `
                                query ($venueId: ID!, $date: DateTime) {
                                    allShows(filter: {
                                            venue: {
                                                id: $venueId
                                            }
                                            date: $date
                                    })  {
                                            id
                                        }
                                }
                            `

        const existentialShowTest = await this.client.request(showQuery, 
            {venueId: venue, date: showInfo.date})

        if (existentialShowTest.allShows.length < 1){

            const addShowQuery =    `
                                        mutation createShow($artistsIds:[ID!], $venueId:ID  ) {
                                            createShow (
                                                artistsIds: $artistsIds
                                                venueId: $venueId
                                                date: "${showInfo.date}"
                                                soldOut: ${showInfo.soldOut}
                                                pit: ${showInfo.pit}
                                                ages: "${showInfo.ages}"
                                                price: "${showInfo.price}"
                                                multiDay: ${showInfo.multiDay}
                                            ) {
                                                id
                                            }
                                        }
                                    `
            const finalResult = await this.client.request(addShowQuery, 
                {venueId: venue, artistsIds: artists})
                .then(data => {
                 const result = data.createShow.id
                 this.logger.info(`FINISH: write show to graphcool as ${result}`)
                 return result
                })
                .catch(error => this.logger.error(error));

            return finalResult

        } else {
            this.logger.info(`FINISH: found show in graphcool`)
            return existentialShowTest.allShows[0]
        }

    }

which first ran a query to make sure that a Show representing the union of a specific date and Venue didn't already exist in graphcool, then ran a mutation to add a Show.

Note that this mutation was specifically structured to take in Ids for existing Venue and Artist objects (the latter in list form) and to attach these as variables in the line:

 client.request(addShowQuery, 
            {venueId: venue, artistsIds: artists})

using the graphql-request library, which allows you to pass a hash of variables into requests to graphcool.

来源：https://stackoverflow.com/questions/48597470/graphql-graphcool-how-to-write-a-mutation-that-links-both-a-oneone-and-a-onem