Node.js - How to get associated model data using graphql? - node.js

Question

In Node.js app, I am using graphql to get the list of data. I have created two models called School and Grade. Association for these models like School has many Grades and Grade belongs to School.
While querying I am getting null value for associated model.
In model school.js,
module.exports = (sequelize, Sequelize) => {
const School = sequelize.define("school", {
name: {
type: Sequelize.STRING,
},
email: {
type: Sequelize.STRING,
},
});
School.associate = function (models) {
School.hasMany(models.Grade, { foreignKey: "school_id" });
};
return School;
};
In typeDefs.graphql,
type Query {
getSchoolDetails: [School]
getSchoolDetail(id: ID!): School
getGradeDetails: [Grade]
}
type School {
id: ID!
name: String
email: String
grades: [Grade]
}
type Grade {
id: ID!
school_id: ID!
name: String
school: School
}
In resolvers.js,
const Query = {
getSchoolDetails: async () => {
try {
const schools = await school.findAll();
return schools;
} catch (err) {
console.log(err);
}
},
getSchoolDetail: async (root, { id }) => {
try {
const scl = await school.findByPk(id);
return scl;
} catch (err) {
console.log(err);
}
},
getGradeDetails: async () => {
try {
const grades = await grade.findAll({});
return grades;
} catch (err) {
console.log(err);
}
},
}
In playground when I query like,
query {
getSchoolDetails{
id
name
email
grades{
name
}
}
}
Output for this is,
{
"data": {
"getSchoolDetails": [
{
"id": "1",
"name": "Rotary West School",
"email": "rotary#gmail.com",
"grades": null
},
{
"id": "2",
"name": "Excel Public School",
"email": "excel#gmail.com",
"grades": null
},
]
}
Same way when I query to get Grades will get school as null. I am learning nodejs relations with graphql, please help me to solve this.

Answer 1

You have to use include with your queries in resolvers.js file like below
getSchoolDetails: async () => {
try {
const schools = await school.findAll({
include: [{ model: Grade }],
});
return schools;
} catch (err) {
console.log(err);
}
},
This Will get all the grades associated with schools
And if you want to include school with grade you have to associate grade with school using Grades belongsTo school