Joseph_Ebuka•2y ago

Assits with relationships

How can i get projects which for members in which thier id is the projectmembers table projects: defineTable({ title: v.string(), description: v.string(), url: v.optional(v.string()), github: v.optional(v.string()), deadline: v.string(), startTime: v.string(), creator: v.id("users"), isCompleted: v.boolean(), coverImage:v.optional(v.string()), }), projectMembers: defineTable({ projectId: v.id("projects"), userId: v.id("users"), role: v.string(), }) .index("by_projectId", ["projectId"]) .index("by_userId", ["userId"]),

11 Replies

erquhart•2y ago

I posed this question to the AI in convex docs and it nailed it: In order to fetch projects for members based on their user ID, you can query the projectMembers table using the index by_userId and the specific userId. Once you have the list of projectMembers documents for the specified user, then you can fetch the related projects by querying the projects table with those projectId values. Here's a pseudo-code example on how to do it:

export const fetchUserProjects = query({
  args: {
    userId: v.id("users"),
  },
  handler: async (ctx, args) => {
    const projectMemberships = await ctx.db
      .query("projectMembers")
      .withIndex("by_userId", (q) => q.eq("userId", args.userId))
      .collect();

    const userProjects = [];
    for (const membership of projectMemberships) {
      const project = await ctx.db
        .query("projects")
        .withId(membership.projectId);
      if (project !== null) {
        userProjects.push(project);
      }
    }

    return userProjects;
  }
});

export const fetchUserProjects = query({
  args: {
    userId: v.id("users"),
  },
  handler: async (ctx, args) => {
    const projectMemberships = await ctx.db
      .query("projectMembers")
      .withIndex("by_userId", (q) => q.eq("userId", args.userId))
      .collect();

    const userProjects = [];
    for (const membership of projectMemberships) {
      const project = await ctx.db
        .query("projects")
        .withId(membership.projectId);
      if (project !== null) {
        userProjects.push(project);
      }
    }

    return userProjects;
  }
});

In this code, we first fetch the projectMembers documents for the given userId``withIndex. Then, for each projectMembers document, we fetch the corresponding projects document using withId method and add them to a list, which is ultimately returned. ---- end of chat gpt output ---- Oh wait, withId() is not a thing lol

Joseph_EbukaOP•2y ago

Thanks @erquhart there’s an ai in convex docs ???

erquhart•2y ago

Yeah, the little chat button next to the search bar at the top

Joseph_EbukaOP•2y ago

Thanks @erquhart How do I go about the withId ?

erquhart•2y ago

It's just db.get(id) Are you trying to get the project for an individual user I think the AI thought you wanted a listing of all project/user pairings

Joseph_EbukaOP•2y ago

Yes am trying to get all the projects for a user

erquhart•2y ago

oh it's many to many There are relationship helpers for this, and that's probably the way you want to go, but here's what I would personally do:

export const fetchUserProjects = query({
  args: {
    userId: v.id('users'),
  },
  handler: async (ctx, args) => {
    const memberProjects = await ctx.db
      .query('projectMembers')
      .withIndex('by_userId', (q) => q.eq('userId', args.userId))
      .collect()
    const projects = await Promise.all(
      memberProjects.map((memberProject) => ctx.db.get(memberProject.projectId))
    )
    return projects
  },
})

export const fetchUserProjects = query({
  args: {
    userId: v.id('users'),
  },
  handler: async (ctx, args) => {
    const memberProjects = await ctx.db
      .query('projectMembers')
      .withIndex('by_userId', (q) => q.eq('userId', args.userId))
      .collect()
    const projects = await Promise.all(
      memberProjects.map((memberProject) => ctx.db.get(memberProject.projectId))
    )
    return projects
  },
})

Okay nevermind it's way simpler with helpers:

export const fetchUserProjects = query({
  args: {
    userId: v.id('users'),
  },
  handler: async (ctx, args) => {
    const projects = await getManyVia(db, "memberProjects", "projectId", "userId", args.userId);
  }
})

export const fetchUserProjects = query({
  args: {
    userId: v.id('users'),
  },
  handler: async (ctx, args) => {
    const projects = await getManyVia(db, "memberProjects", "projectId", "userId", args.userId);
  }
})

Joseph_EbukaOP•2y ago

while the second one seems easier i do not understand how it works but the first seems understandable Thanks again @erquhart the getManyVia function is not defined would i have to import it?

erquhart•2y ago

Yes, you can install the helpers via npm:

npm install convex-helpers

npm install convex-helpers

Relationship helpers need to be imported from the relationships file:

import { getManyVia } from 'convex-helpers/server/relationships'

import { getManyVia } from 'convex-helpers/server/relationships'

erquhart•2y ago

Explainer on getManyVia(): https://stack.convex.dev/functional-relationships-helpers#many-to-many

Functional Relationships: Helpers

In this post, we’ll look at some helper functions to help write code to traverse relationships in a readable, predictable, and debuggable way.

Joseph_EbukaOP•2y ago

Thanks @erquhart

Assits with relationships

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