add support for many-to-many relationships in json2graphql

[wawhal]

Moved from hasura/json2graphql.
Originally opened by: @FrediBach

[FrediBach]

Copying of my last post from json2graphql:

I think the best solution would be:

users: [
    { id: 1, username: 'user1', user_ids: [2, 3] },
    { id: 2, username: 'user2', user_ids: [1] },
    { id: 3, username: 'user3', user_ids: [] },
    { id: 4, username: 'user4', user_ids: [1, 2, 3] },
]

We already have the _id naming convention for single relationships, so using _ids would be the logical solution for multiple.

And we could always combine this with the named key naming convention:

users: [
    { id: 1, username: 'user1', friends__user_ids: [2, 3] },
    { id: 2, username: 'user2', friends__user_ids: [1] },
    { id: 3, username: 'user3', friends__user_ids: [] },
    { id: 4, username: 'user4', friends__user_ids: [1, 2, 3] },
]

I've updated Blowson to correctly handle arrays like in the example above: https://github.com/FrediBach/Blowson

[FrediBach]

I've added support for custom key names in Blowson version 0.9 :-)

[chunsli]

any chance there will be support for many-to-many relationships soon, its a pretty common use case these days

[ivawzh]

When you implement the many2many feature, would you please also keep in mind to support (even in further future) junction table filters?

Say I have tables a, b and c.
b is the junction table link between a and c.
b itself has status is_active: boolean.
I need to get the distinct set of c associated with a through active-only b.

I guess to support that filter will have some impact on the query argument interface.

Thanks in advance

[wawhal]

@chunsli @ivawzh no work is being done on this issue currently and we are not sure when we will get to it. Just informing if in case it is blocking one of you folks?

We're open to contributions. It'll be really appreciated if somebody can work on this <3

[rv404674]

@wawhal Hi wawhal. This seems interesting and the only issue that seems not be taken. I am a complete newbie and have never used Hasura. Is it a good issue for me. I am willing to learn hasura and can also dive in the codebase. If yes, can you assign it to me?

Thanks.

[marionschleifer]

@rv404674 we don't assign issues for Hacktoberfest. Here are the guidelines you can follow for contributions: https://github.com/hasura/graphql-engine/wiki/Hacktoberfest-2019-%F0%9F%8E%89. If there is a draft PR linked to the issue, it means someone is working on it 🙂