Check if an user exist in my database with Node and MySQL [duplicate] - mysql

Question

I need to check if entry with specific ID exists in the database using Sequelize in Node.js
function isIdUnique (id) {
db.Profile.count({ where: { id: id } })
.then(count => {
if (count != 0) {
return false;
}
return true;
});
}
I call this function in an if statement but the result is always undefined
if(isIdUnique(id)){...}

Answer 1

I don't prefer using count to check for record existence. Suppose you have similarity for hundred in million records why to count them all if you want just to get boolean value, true if exists false if not?
findOne will get the job done at the first value when there's matching.
const isIdUnique = id =>
db.Profile.findOne({ where: { id} })
.then(token => token !== null)
.then(isUnique => isUnique);

Answer 2

Update: see the answer which suggests using findOne() below. I personally prefer; this answer though describes an alternative approach.
You are not returning from the isIdUnique function:
function isIdUnique (id) {
return db.Profile.count({ where: { id: id } })
.then(count => {
if (count != 0) {
return false;
}
return true;
});
}
isIdUnique(id).then(isUnique => {
if (isUnique) {
// ...
}
});

Answer 3

You can count and find.
Project
.findAndCountAll({
where: {
title: {
[Op.like]: 'foo%'
}
},
offset: 10,
limit: 2
})
.then(result => {
console.log(result.count);
console.log(result.rows);
});
Doc link, v5 Beta Release

Answer 4

I found the answer by #alecxe to be unreliable in some instances, so I tweaked the logic:
function isIdUnique (id, done) {
db.Profile.count({ where: { id: id } })
.then(count => {
return (count > 0) ? true : false
});
}

Answer 5

As Sequelize is designed around promises anyway, alecxe's answer probably makes most sense, but for the sake of offering an alternative, you can also pass in a callback:
function isIdUnique (id, done) {
db.Profile.count({ where: { id: id } })
.then(count => {
done(count == 0);
});
}
}
isIdUnique(id, function(isUnique) {
if (isUnique) {
// stuff
}
});

Answer 6

Extending #Jalal's answer, if you're very conscious about performance implications while maintaining a simple Sequelize structure and you do not need the row data, I suggest you only request one column from the database. Why waste bandwidth and time asking the database to return all columns when you won't even use them?
const isIdUnique = id =>
db.Profile.findOne({ where: { id }, attributes: ['id'] })
.then(token => token !== null)
.then(isUnique => isUnique);
The attributes field tells Sequelize to only request the id column from the database and not sending the whole row's content.
Again this may seem a bit excessive but at scale and if you have many columns that hold a lot of data, this could make a giant difference in performance.

Answer 7

Try the below solution. I tried it and it works well.
const isIdUnique = async (id, model) => {
return await model.count({ where: { id: id } });
};
const checkExistId = await isIdUnique(idUser, User);
console.log("checkExistId: ", checkExistId);