Right way to extend schema in .meshrc.yml

[appcoders]

I got a mySQL database which has articles in it. Articles can have categories and labels.

There are the following tables:

article (id, title, content)
article_to_categories (article_id, category_id)
article_categories ( id, parent_id, title)
labels_articles (article_id, label)

Now I get the following schema:

type articles {
  id: Int!
  title: String!
  content: String!
}

type article_to_categories {
  article_id: Int!
  category_id: Int!
  articles(where: articles_WhereInput, orderBy: articles_OrderByInput, limit: Int, offset: Int): [articles]
  article_categories(where: article_categories_WhereInput, orderBy: article_categories_OrderByInput, limit: Int, offset: Int): [article_categories]
}

type article_categories {
  id: Int!
  parent_id: Int
  title: String!
  article_categories(where: article_categories_WhereInput, orderBy: article_categories_OrderByInput, limit: Int, offset: Int): [article_categories]
}

type labels_articles {
  article_id: Int!
  label: String!
  articles(where: articles_WhereInput, orderBy: articles_OrderByInput, limit: Int, offset: Int): [articles]
}

What I want to achieve is that in articles I get something like this:

type articles {
  id: Int!
  title: String!
  content: String!
  **categories**
  **labels**
}

And in categories :

type article_categories {
  id: Int!
  parent_id: Int
  title: String!
  article_categories(where: article_categories_WhereInput, orderBy: article_categories_OrderByInput, limit: Int, offset: Int): [article_categories]
 **parent_categories**
}

How can I achieve this?

Thanks for help!

[charlypoly]

Hi @appcoders 👋🏼

Could you also provide the list of the GraphQL queries that match your initial SQL schema? (the one SQL schema generated by the @graphql-mesh/sql handler I guess)
This would help us in giving you a more complete example of Schema custom resolvers with GraphQL Mesh.

In the meantime, please know that our documentation provides a complete example (with a linked repository) that reproduces a use-case similar to yours: https://www.graphql-mesh.com/docs/getting-started/combine-multiple-sources#setup-hierarchy-with-nested-queries

Best,

[appcoders]

Hi @charlypoly,

currently I am stuck here:

additionalTypeDefs: |
  extend Type articles {
    categories: article_categories
  }
additionalResolvers: 
  - targetTypeName: articles
    targetFieldName: categories
    sourceName: article_categories
    sourceFieldName: ???

As the only generated query from sql is:

type Query {
article_categories(limit: Int, offset: Int, where: article_categories_WhereInput, orderBy: article_categories_OrderByInput): [article_categories]
}
input article_categories_WhereInput {
  id: String
  parent_id: String
  title: String
}

[charlypoly]

Okay, so, regarding you target query design, your configuration should be similar to:

additionalTypeDefs: |
  extend type articles {
    categories: article_categories
  }
additionalResolvers: 
  - targetTypeName: articles
    targetFieldName: categories
    sourceName: deskpro
    sourceTypename: Query
    sourceFieldName: article_categories
    requiredSelectionSet:
      |
      {
        id
      }
    sourceArgs: # What args does this need to take?
      where.id: "{root.id}"

Let's decompose the above additionalResolvers configuration:

targetTypeName and targetFieldName express that we want to add a new field called categories to articles.
For this, we need to provide the Source name via sourceName.
Then for the given source, which type and field we should get articles.categories's data resolved from (sourceTypename and sourceFieldName).
Finally, we need to specify that articles.id should be forward to the source Query.article_categories query as the where.id input argument.

It is quite verbose, but know that we are working on improving it.

I'll be better able to help you with a Github reproduction repository since I need to get a better visibility of the source Schema to provide a complete working configuration.

[appcoders]

Makes sense. I prepare a repo.

[appcoders]

Here you find a repo with the database via docker. https://github.com/appcoders/-graphqlmesh-many-to-many-relations

[appcoders]

The result that I want from my query

query MyQuery {
  articles {
    content
    id
    title
    categories {
      title     
      }
  }
}

should be - notice that article with id 5 has two categories assigned.

{
  "data": {
    "articles": [
      {
        "content": "This is content of article #1",
        "id": 1,
        "title": "Article #1",
        "categories": [
          {
            "title": "Root Category"
          }
        ],
      },
      {
        "content": "This is content of article #2",
        "id": 2,
        "title": "Article #2",
        "categories": [
          {
            "title": "Sub-Category to root"
          }
        ],
      },
      {
        "content": "This is content of article #3",
        "id": 3,
        "title": "Article #3",
        "categories": [
          {
            "title": "Sub-Category Level 2"
          }
        ],
      },
      {
        "content": "This is content of article #4",
        "id": 4,
        "title": "Article #4",
        "categories": [
          {
            "title": "Root Category #2"
          }
        ],
      },
      {
        "content": "This is content of article #5",
        "id": 5,
        "title": "Article #5",
		"categories": [
          {
            "title": "Root Category"
          },
          {
            "title": "Root Category #2"
          }
        ],
      },
      {
        "content": "This is content of article #6",
        "id": 6,
        "title": "Article #6",
        "categories": [
          {
            "title": "Root Category"
          }
        ],
      },
      {
        "content": "This is content of article #7",
        "id": 7,
        "title": "Article #7",
        "categories": [
          {
            "title": "Sub-Category to root"
          }
        ],
      },
      {
        "content": "This is content of article #8",
        "id": 8,
        "title": "Article #8",
        "categories": [
          {
            "title": "Sub-Category Level 2"
          }
        ],
      }
    ]
  }
}

[charlypoly]

@appcoders
Thank you for your repository, way simpler this way! ⚡

please find a working example here: appcoders/-graphqlmesh-many-to-many-relations#1

[appcoders]

type Query {
article_to_categories(limit: Int, offset: Int, where: article_to_categories_WhereInput, orderBy: article_to_categories_OrderByInput): [article_to_categories]
}
input article_to_categories_WhereInput {
  article_id: String
  category_id: String
}

[ardatan]

I've read the conversation and I think you need something like following which looks a bit complicated but instead we can handle this kind of relationships automatically in Mesh. @appcoders Please see my PR;
#3993
And you can test it with the canaries CI pushes and It will post the versions as a comment soon

[appcoders]

Hi @ardatan,
In the meantime I prepared a repo where I continued to discussion with @charlypoly.
appcoders/-graphqlmesh-many-to-many-relations#1 (comment)
I installed @graphql-mesh/[email protected] to test with and now I can see the relation in GraphiQL Explorer:

Screenshot GraphiQL Explorer

When I run this query:

query MyQuery {
  articles {
    article_to_categories {
      article_categories {
        id
        title
      }
    }
    title
    id
  }
}

I get this result:

{
  "data": {
    "articles": [
      {
        "article_to_categories": [
          {
            "article_categories": [
              {
                "id": 1,
                "title": "Root Category"
              }
            ]
          }
        ],
        "title": "Article #1",
        "id": 1
      },
      {
        "article_to_categories": [
          {
            "article_categories": [
              {
                "id": 1,
                "title": "Root Category"
              }
            ]
          }
        ],
        "title": "Article #2",
        "id": 2
      },
      {
        "article_to_categories": [
          {
            "article_categories": [
              {
                "id": 1,
                "title": "Root Category"
              }
            ]
          }
        ],
        "title": "Article #3",
        "id": 3
      },
      {
        "article_to_categories": [
          {
            "article_categories": [
              {
                "id": 1,
                "title": "Root Category"
              }
            ]
          }
        ],
        "title": "Article #4",
        "id": 4
      },
      {
        "article_to_categories": [
          {
            "article_categories": [
              {
                "id": 1,
                "title": "Root Category"
              }
            ]
          }
        ],
        "title": "Article #5",
        "id": 5
      },
      {
        "article_to_categories": [
          {
            "article_categories": [
              {
                "id": 1,
                "title": "Root Category"
              }
            ]
          }
        ],
        "title": "Article #6",
        "id": 6
      },
      {
        "article_to_categories": [
          {
            "article_categories": [
              {
                "id": 1,
                "title": "Root Category"
              }
            ]
          }
        ],
        "title": "Article #7",
        "id": 7
      },
      {
        "article_to_categories": [
          {
            "article_categories": [
              {
                "id": 1,
                "title": "Root Category"
              }
            ]
          }
        ],
        "title": "Article #8",
        "id": 8
      }
    ]
  }
}

which is wrong as it always returns the article_categories for article_id = 1.

[ardatan]

My bad I missed that in our test snapshots. Could you try with this one more time?
@graphql-mesh/[email protected]

[appcoders]

@ardatan I tried - thank you very much 🥇 works as intended. Do you know when this PR be part of the next release?
@charlypoly As this is fixed on mysql side an additonalResolver and additionalTypeDefs are no longer needed to handle this kind of many-to-many relations.

[ardatan]

#3995
Released :) Will be available in a few minutes

[appcoders]

@ardatan Awesome made my day 🌞