I have a local postgres database running on my machine. I use node.js to access it. I have a table called 'friends' where every row is a user and a friend. I also have a table called 'users' where every row has all basic info about a user(e.g name and such).
When I want to remove a friendship between two users I have to remove two rows from the 'friends' table. I do this with this function:
const removeFriend = async (clientId, friendId) => {
// initiate transaction
return db
.transaction((trx) => {
// remove friendship from client
trx('friends')
.where({ user_id: clientId, friend_id: friendId })
.del()
.then(() => {
// remove friendship from friend
return trx('friends').where({ user_id: friendId, friend_id: clientId }).del();
})
// if all good then commit
.then(trx.commit)
// if bad then rollback
.catch(trx.rollback);
})
.catch(() => 'error');
};
I call the removeFriend function this way removeFriend(clientId, friendId)
Then when i want to get a list of all friends with their names from the database i use this function:
const getUserFriends = async (clientId) => {
// get friends
return db('friends')
.where({ user_id: clientId })
.join('users', 'users.id', 'friends.friend_id')
.select('friends.friend_id', 'users.name')
.then((friends) => friends)
.catch(() => 'error');
};
I call the getUserFriends function this way await getUserFriends(clientId)
The problem is that when I use removeFriend function and then directly use the getUserFriends function i get a list where the users are still friends. However, If i look in the database the rows have been deleted so naturaly i should get a list where the users are not friends. Do I use the await wrong or something?
Related
I need to delete and insert the same data to the table.
But currently ,after the delete processes it seems that the data are still in the database. I think this was a soft-delete only. I cannot insert the same data to the DB since there are items that are supposed to be unique and it is not deleted from the DB.
After the deleteResults function, I assumed that the items are now deleted to the database, but when the insertQuestions is called, it encounters an error which is some data are the same with the data in the DB.
My model is not set as paranoid so I cannot use the force property.
How to hard-delete in Sequelize?
Here is the code for delete and insert implementation:
const res = await <<Model>>.destroy({
where: {
id: id
},
transaction: transaction
})
// This contains the destroy calls
const deleteResults = await deleteQuestions(questionnaireResult.id, questionnaireResult.qneQuestions, transaction);
//Insert to DB
const insertQuestionsResult = await insertQuestions(questionnaireResult.id, null, qsReponseObj.questions, answerTypes, languages, sortValuesQuestion, transaction);
Note that they are using the same transaction.
You are using transaction to do these two operations but seems did not call commit() function. I did a simple test on my local, before I run my code, data in users table:
After I run the code below, delete the record with id of value 2 and insert a new record with id 2 but new user name:
class Users extends Model {}
Users.init({
name: DataTypes.STRING
}, { sequelize, modelName: 'users' });
(async () => {
const t = await sequelize.transaction();
await Users.destroy({
where: {
id: 2
},transaction: t
});
await Users.create({
id:2,
name:"a new user name"
},{transaction:t})
await t.commit();
})().then(()=>{sequelize.close()})
.catch(error =>{console.log(error)})
Result:
I'm trying to update all users from an array in mongoose, but I don't know how to do that.
I'm parsing all users from MongoDB database to an array, then I'm editing values in this array and I need to save array back to the database.
Parsing all users from the database:
let users = []
async function loadUser() {
users = await User.find({}) // User is Schema
}
Then I'm trying to save all of them, but it isn't working.
async function saveUsers () {
users.forEach(user => { // maybe there's other way to do save, but I don't found it.
User.updateOne(user, user, function (err) {
if (err) throw err
})
})
}
You can use forEach as follow:
users.forEach(function(user)){
User.update({"_id": user._id}, {"$set": {"value": user.value }}, callback);
});
I'd like to update some data in Mongoose by using array value that I've find before.
Company.findById(id_company,function(err, company) {
if(err){
console.log(err);
return res.status(500).send({message: "Error, check the console. (Update Company)"});
}
const Students = company.students;
User.find({'_id':{"$in" : Students}},function(err, users) {
console.log(Students);
// WANTED QUERY : Update company = null from Users where _id = Students[];
});
});
Students returns users._id in array with object inside, and I use that to find users object, and then I want to set null a field inside users object, that field named as "company". How I can do that? Thank you.
From what you posted (I took the liberty to use Promises but you can roughly achieve the same thing with callbacks), you can do something like:
User.find({'_id':{"$in" : Students}})
.then( users =>{
return Promise.all( users.map( user => {
user.company = null;
return user.save()
}) );
})
.then( () => {
console.log("yay");
})
.catch( e => {
console.log("failed");
});
Basically, what I'm doing here is making sure .all() user models returned by the .find() call are saved properly, by checking the Promised value returned for .save()ing each of them.
If one of these fails for some reasons, Promise.all() return a rejection you can catch afterhand.
However, in this case, each item will be mapped to a query to your database which is not good. A better strategy would be to use Model.update(), which will achieve the same, in, intrinsically, less database queries.
User.update({
'_id': {"$in": Students}
}, {
'company': <Whatever you want>
})
.then()
use .update but make sure you pass option {multi: true} something like:
User.update = function (query, {company: null}, {multi: true}, function(err, result ) { ... });
Let us assume that we have two collections say "users" and "usersList"
Upon creating a new user document in users collection with following object
{username: Suren, age:31}
The function should read the above data and update other collection i.e. "usersList" with the username alone like below
{username: Suren}
Let me know the possibility
The code I have tried is
exports.userCreated =
functions.firestore.document('users/{userId}').onCreate((event) => {
const post = event.data.data();
return event.data.ref.set(post, {merge: true});
})
I have done it using below code
exports.userCreated = functions.firestore.document('users/{userId}')
.onCreate((event) => {
const firestore = admin.firestore()
return firestore.collection('usersList').doc('yourDocID').update({
name:'username',
}).then(() => {
// Document updated successfully.
console.log("Doc updated successfully");
});
})
If all you want to do is strip the age property from the document, you can do it like this:
exports.userCreated = functions.firestore.document('users/{userId}').onCreate((event) => {
const post = event.data.data();
delete post.age;
return event.data.ref.set(post);
})
In my /api/v1/chats POST route I make an async call to user_chat_queries.addUserChat for each user_id passed in the request body. The idea is that if lots of user_id's come in I don't want to have each insertion await, instead I'd like to to dispatch all the insertions asynchronously so I do:
Asynchronous Route handler (https://github.com/caseysiebel/lang-exchange/blob/master/src/server/routes/chats.js#L57):
await Promise.all(user_ids.map((user_id) => {
return user_chat_queries.addUserChat(user_id, chat.id)
}));
As opposed to,
Synchronously:
for (let user_id of user_ids) {
await user_chat_queries.addUserChat(user_id, chat.id)
}
And in the user_chat_queries (https://github.com/caseysiebel/lang-exchange/blob/master/src/server/db/queries/user_chat.js#L5):
addUserChat: ( async (user_id, chat_id) => {
const user_chat = await userChats
.insert({ user_id, chat_id })
.returning('*')
const data = await db('user_chat').select('*')
return user_chat;
}),
Now the route is accessed from my test file: (https://github.com/caseysiebel/lang-exchange/blob/master/test/routes.chats.test.js#L83)
it('should add 2 user_chats', (done) => {
chai.request(server)
.post('/api/v1/chats')
.send({
created_at: Date.now(),
user_ids: [ 2, 4 ]
})
.end((err, res) => {
should.not.exist(err);
res.status.should.equal(201);
res.type.should.equal('application/json');
res.body.status.should.eql('success');
const chat = res.body.data;
chat.should.include.keys('id', 'created_at');
knex('user_chat')
.select('*')
.then((data) => console.log('data', data))
done();
});
});
The log shows that the { user_id: 4, chat_id: 3 } in inserted in the user_chat table twice.
The expected result (and the result when executed synchronously) is one { user_id: 2, chat_id: 3 } record and one { user_id: 4, chat_id: 3 } record are inserted into the user_chat table.
I can't track down what is causing this. It seems to me that addUserChat should insert a record made from the inputs it is passed each time, regardless of when it resolves.
Full code base: https://github.com/caseysiebel/lang-exchange
Debugging console output: https://gist.github.com/caseysiebel/262997efdd6467c72304ee783dadd9af#file-console-L5
you need to use mapSeries type mechanism (Which is not available on default Promise API). So, you may need to use other 3rd party library like bluebird.
more details bluebird mapSeries
You don't show what userChats is in your code examples, but it looks like you may have a global instance of knex that you reuse across different queries, such as:
const userChats = knex('user_chats')
This is not safe because each query building operation mutates the query builder. You may get away with it if you're running in series but when you run in parallel, both your addUserChat calls are using the same userChats query builder at the same time and weird stuff happens.
Rule of thumb: call knex() once for every query you build.