I have three PostgreSQL tables defined in Sequelize: AccountTypes, Accounts and Users.
Using a base AccountType, I want to find all Accounts (hasMany) that ALSO belongs to a certain user. The appropriate table associations are defined.
In order words, I want to turn this...
return db.instances.AccountType.getLedger('USD').then(ledger => {
return ledger.getAccounts().then(accounts => {
accounts.forEach(account => {
account.getUser() // <-- horribly inefficient
})
});
});
Into some like this...
// assume 'user' contains a retrieved User model
return db.instances.AccountType.getLedger('USD').then(ledger => {
return ledger.getAccounts({where: user}).then(accounts => {
// now 'accounts' will be filtered by Accounts.UserId === user.id
});
});
My model associations allow user.getAccounts(), but then I'm stuck with the same issue -- wanting to filter a record's associations by model, without resorting to raw SQL.
I can do an ugly/hacky include, like:
return db.instances.AccountType.getLedger('USD').then(ledger => {
return ledger.getAccounts({include:{model: db.models.User, where: {UserId: user.id}}}).then(accounts => {
// now 'accounts' is joined by user, but I've also loaded a bunch of fields I don't need
});
});
But this is intended to join another table, which I don't want. I just want to return any Accounts row where Accounts.UserID === user.id, without looking up any other table.
Is there any function in Sequelize where I could just throw at it a ready-made model, and it'll figure out which fields should wire up to which?
Related
I am working on a social network web application I have established a system of following followers with firebase and node js , so I created a collection users and in it two following followers array, I managed to add them
Now I want to issue a condition to check if the user has already made a follow up not to add it a second time to the table how can i access to the tables (following, followers)in order to verify if the user is in
exports.onFollow = (req, res) => {
const followDocument = db.doc(`/users/${req.body.email}`);
const followerDocument = db.doc(`/users/${req.user.email}`);
let followData;
let followerData;
followDocument
.get()
.then((doc) => {
if (doc.exists) {
followData = doc.data();
if ('req.user.email', 'in', followData.followers.docs) {
return res.status(200).json({
error: 'user already follow'
});
} else {
followData.followers.push(req.user.email);
return followDocument.update({
followers: followData.followers
});
}
}
})
.catch((err) => {
console.error(err);
res.status(500).json({
error: err.code
});
});
It sounds like you want followers to be an array with unique values, so that each email address can only occurs once. Firestore has special arrayUnion operation for adding values to such a field.
From the documentation on updating elements in an array:
If your document contains an array field, you can use arrayUnion() and arrayRemove() to add and remove elements. arrayUnion() adds elements to an array but only elements not already present. arrayRemove() removes all instances of each given element.
var washingtonRef = db.collection("cities").doc("DC");
// Atomically add a new region to the "regions" array field.
washingtonRef.update({
regions: admin.firestore.FieldValue.arrayUnion("greater_virginia")
});
// Atomically remove a region from the "regions" array field.
washingtonRef.update({
regions: admin.firestore.FieldValue.arrayRemove("east_coast")
});
I'd recommend switching to using arrayUnion() for your use-case, as it prevents having to do the query to detect if the email address is already in the array.
I am trying to write a transaction that first query documents by documentId from a list of ids, then makes some updates.
I am getting the error:
The corresponding value for FieldPath.documentId() must be a string or a DocumentReference.
For example:
const indexArray = [..list of doc ids...]
const personQueryRef = db.collection("person").where(admin.firestore.FieldPath.documentId(), "in", indexArray)
return db.runTransaction(transaction => {
return transaction.get(personQueryRef).then(personQuery => {
return personQuery.forEach(personRef => {
transaction.update(personRef, { ...update values here })
//more updates etc
})
})
})
I am wanting to do this in an onCreate and onUpdate trigger. Is there another approach I should be taking?
Update
The error still persists when not using a transaction, so this is unrelated to the problem.
The problem does not occur when the query is .where(admin.firestore.FieldPath.documentId(), "==", "just_one_doc_id"). So, the problem is with using FieldPath.documentId() and in.
It sounds like the type of query you're trying to do just isn't supported by the SDK. Whether or not that's intentional, I don't know. But if you want to transact with multiple documents, and you already know all of their IDs, you can use getAll(...) instead:
// build an array of DocumentReference objects
cost refs = indexArray.map(id => db.collection("person").doc(id))
return db.runTransaction(transaction => {
// pass the array to getAll()
return transaction.getAll(refs).then(docs => {
docs.forEach(doc => {
transaction.update(doc.ref, { ...update values here })
})
})
})
Let's say I have a bookshelf one to many relation Person => Cars, where
Pseudocode
# Person
hasMany: cars
id
name
# Car
belongsTo: person
id
make
Now I'd like to find all persons who own a 'Rover'.
What I'd was naively hoping for was something like this, which is obviously not working:
Person.query({ where: { cars: { make: 'Rover' } } } )
It looks like there is no really elegant solution. I solved my problem finally, by using joins.
Which looks like this:
Person.query((qb) => {
qb.join('cars', 'cars.person_id', 'person.id');
// no that the cars are joined,
// they are available for querying
qb.where({'cars.make': 'Rover'});
})
.then((result) => {
// do stuff
})
.catch((err) => {
// always catch errors
console.error(err);
});
It gets a little more complicated, when you want to query against the counterpart of a of many-to-many relation with pivot/intermediate table but maybe this helps to get started.
You need to use withRelated option to fetch a related model. Try this,
Person.forge()
.fetchAll({
withRelated: [{
cars: function(qb) {
qb.where({make: 'Rover'})
}
}]
})
.then(function(persons) {
//do something
});
More from the docs here
Been trying to find samples usage for some of the static methods for a persistedModel in Loopback.
https://apidocs.strongloop.com/loopback/#persistedmodel-prototype-updateattribute
it just says:
persistedModel.updateAttributes(data, callback)
But how you I choose the which record I want to update? this is not working for me.
var order = Order.setId('whateverrecordId');
order.updateAttributes({name:'new name'},callback)
Loving loopback.. but their doc, sucks.. :(
You can use those on event listener like AfterSave
example:
Model.observe('after save', function(ctx, next) {
ctx.instance.updateAttribute(fieldname:'new value');
next();
});
1- What you did was right but i do not advise this method it's used for instance methods and generally to update fields like date for all the collection that you have so you don't need an id for it.
But you can try to make an array containing data to update containing also the ids and then make a comparison to fill in data for the ids that you have. (in #dosomething)
order.find().then(function(orders) {
orders.forEach(function(element) {
order.setId(element.id);
#DoSomething
order.updateAttribute({new: data}, function(err, instance) {
console.log(instance);
})
});
})
2- You can use updateAll to update one or many attribute.
PersistedModel.updateAll([where], data, callback)
var Updates = [{id : 1, name: name1}, ...]
Updates.forEach(function(element) {
order.updateAll({id : element.id}, {name :element.name}, function(err, count) {
if (err) {
console.error(err);
}
console.log(count); // number of data updated
})
})
I'm using Bookshelf.js/Knex.js, fetching a model (call it user) with a related child model (call it company).Can I order by a field on the child model - company.name?
Also, if that's possible, can I multi sort, say company.name descending then lastName ascending
Here's my current code, which only works on root model fields. qb.orderBy('company.name', 'desc') doesn't work.
users.query(function(qb) {
qb.orderBy('lastName', 'asc');
})
.fetch({withRelated: ['company']})
.then(success, error);
Try the following:
users
.fetch({withRelated: [
{
'company': function(qb) {
qb.orderBy("name");
}
}
]})
.then(success, error);
I got the idea from https://github.com/tgriesser/bookshelf/issues/361
You can do it like this without the need of a function:
users.query(function(qb) {
qb.query('orderBy', 'lastName', 'asc');
})
.fetch({withRelated: ['company']})
.then(success, error);
Found here: Sort Bookshelf.js results with .orderBy()
I think I solved it by doing this:
let postHits =
await posts
.query(qb => qb
.innerJoin('post_actor_rel', function () {
this.on('post.id', '=', 'post_actor_rel.post_id');
})
.innerJoin('actor', function () {
this.on('post_actor_rel.actor_id', '=', 'actor.id');
})
.orderByRaw('actor.name ASC')
.groupBy('id')
)
.fetchPage({
withRelated: ['roles', 'themes', 'activity_types', 'subjects', 'educational_stages', 'images', 'documents', 'actors'],
limit,
offset
},
);
I modify the query by inner joining with the desired tables and after sorting (using orderByRaw since I will need to add some more sorting that I think is not possible with orderBy) I group by the post's id to get rid of the duplicate rows. The only problem is that it's not defined which actor name (of several possible) is used for the sorting.