I have a GraphQL API which is supposed to return data from MySQL and PostGres database. In the resolvers, I have console.log the results and can view the data in the terminal.
address: {
type: AddressType,
description: "An Address",
args: {
id: { type: GraphQLInt },
},
resolve: (parent, args) => {
// Make a connection to MySQL
let result;
connection.query(
`SELECT * FROM addresses WHERE id = ${args.id}`,
(err, res, fields) => {
if (err) console.log(err);
console.log("========");
console.log(res);
console.log("+++++++++");
console.log(res[0]);
// console.log(result);
}
);
return result;
},
},
In the terminal, I can see the results when I run the query on GraphiQL:
[nodemon] starting `node schema.js`
Server is running
Connected to PSQL database.
Connected to mySQL database.
========
[
RowDataPacket {
id: 1,
address_type: 'House',
status: 'Inactive',
entity: 'Building',
number_and_street: 'PO BOX 276',
suite_and_apartment: 'PO',
city: 'Ennis',
postal_code: '59729-0276',
country: 'USA',
notes: 'Dolorem quia repellendus et et nobis.',
created_at: 2020-12-18T05:00:00.000Z,
updated_at: 2021-05-21T04:00:00.000Z,
latitude: null,
longitude: null
}
]
+++++++++
RowDataPacket {
id: 1,
address_type: 'House',
status: 'Inactive',
entity: 'Building',
number_and_street: 'PO BOX 276',
suite_and_apartment: 'PO',
city: 'Ennis',
postal_code: '59729-0276',
country: 'USA',
notes: 'Dolorem quia repellendus et et nobis.',
created_at: 2020-12-18T05:00:00.000Z,
updated_at: 2021-05-21T04:00:00.000Z,
latitude: null,
longitude: null
}
However on GraphiQL, I get null for data. Input:
{
address(id: 1) {
address_type
}
}
output:
{
"data": {
"address": null
}
}
I am very new to GraphQL. What could I be missing here? I am attempting to get this information from the terminal to show upon query in GraphiQL. Just trying to learn more.
The classic problem with inattention:
You use the res variable for the console. And nowhere are you assigning a value to result.
And the return result is executed before the query is executed. (out of context where you have data)
See the documentation for how to use the async / await syntax. You are currently using callbacks - which is not a recommended syntax.
Not sure, but should be something like, you should use async/await, and await the return of query data. Also be sure to assign the value to the variable you have:
address: {
type: AddressType,
description: "An Address",
args: {
id: { type: GraphQLInt },
},
resolve: async (parent, args) => {
const result = await connection.query('SELECT * FROM addresses WHERE id = $1', [args.id]);
return result;
},
},
What ended up working for me was the following:
address: {
type: AddressType,
description: "An Address",
args: {
id: { type: GraphQLInt },
},
resolve: async (parent, args) => {
const [rows, fields] = await promisePool.query(
`SELECT * FROM addresses WHERE id = ${args.id}`
);
console.log(rows[0]);
return rows[0];
},
},