Develop Reference

Sequelize and defaultScope with Models associated

I am using Sequelize with Express, and Node js and I am trying to define defaultScope for Models.
Card and Tag have a Many To Many association.
Here are Models definitions and addScope
// Models Associations
// ONE TO MANY
List.hasMany(Card, {
as: "cards",
});
Card.belongsTo(List, {
as: "list",
});
// MANY TO MANY
Card.belongsToMany(Tag, {
as: "tags",
through: "card_has_tag",
updatedAt: false,
});
Tag.belongsToMany(Card, {
as: "cards",
through: "card_has_tag",
updatedAt: false,
});
// SCOPES
Card.addScope("defaultScope", {
include: {
association: "tags",
},
});
List.addScope("defaultScope", {
include: {
association: "cards",
include: "tags",
},
});
// What I would like to implement
// If I comment lines below => List and Card queries are working
Tag.addScope("defaultScope", {
include: {
association: "cards",
},
});
I would like to print by default all related infos with associated relations.
I want to get this info when I execute a sequelize query for each model.
LISTS with associated :
cards
tags
CARDS with associated:
tags
TAGS with associated :
cards
I manage to get 1 & 2, but when I add Tag.addScopenothing is working anymore.
When I change defaultScope by another string by defining a scope all (for example) , and when I use model.scope("all").findAll(), this is working, but it is not what I would like to do becaue I want to use defaultScope to have a default behavior so I don't have to specify scope in queries command like (findAll...)
Is there a way I can do that ?

The way you are trying to set it up results in an endless recursion, you simply can't have it like that.
If you set it up like that and query Card it will include Tag which will include Card which will include Tag and so on until you get Maximum call stack size exceeded.
There is a workaround you can use, which is to add another scope which includes nothing, then specify that scope for the model in the defaultScope.
Tag.addScope("noInclude", {});
Card.addScope("noInclude", {});
Tag.addScope("defaultScope", {
include: [
{
model: Card.scope("noInclude"),
as: "cards"
}
]
});
Card.addScope("defaultScope", {
include: [
{
model: Tag.scope("noInclude"),
as: "cards"
}
]
});
This should give you the desired behaviour.

Only download Firebase snapshots that have child key

My data structure looks like this (removed unnecessary parts):
{
"threads" : {
"PUSHID" : {
"info" : {
"members" : {
"uid" : true,
"uid2" : true
}
}
}
}
}
I'm trying to write some javascript to pull snapshots of threads a user is in, but I can't figure out a way for it to work without pulling snapshots of each thread. This is my code now that pulls each thread snapshot.
firebase.database().ref('threads').on('child_added', function(snapshot) {
if (snapshot.hasChild('info/members/' + userUid)) {
// Display thread info
}
});
I tried to make a query with .orderByChild('info/members/' + userUid) and removing null snapshots, but I would have to add a .indexOn for each userUid which is obviously not practical.

Your current structure makes it easy/efficient to look up the users for a thread. But your use case is to look up the threads for a user. You'll need to augment your data model to allow the use-case:
{
"user_threads" : {
"uid": {
"PUSHID": true,
"PUSHID2": true
},
"uid2": {
"PUSHID": true,
"PUSHID3": true
}
}
}
And then read it with:
firebase.database().ref('user_threads/'+userUid).on('child_added', function(snapshot) {
...
});
Modifying/expanding your data model to match the use-cases of your app is quite common when using NoSQL databases.

Sequelize Migration: update model after updating column attributes

I will get through to the point already. I'm having a problem of updating the rows after I have changed the status column attribute.
up: function(queryInterface, Sequelize) {
return queryInterface.changeColumn('projects', 'status', {
type: Sequelize.ENUM('processing', 'unassigned', 'ongoing', 'completed'),
allowNull: false,
defaultValue: 'unassigned'
}).then(function() {
return Project.update({
status: 'unassigned'
}, {
where: {
status: 'processing'
}
});
});
}
The Project.update() seems not working in any case but changing the attributes of the column works.
Any idea guys? I'm somehow a newbie in sequelize and any idea would be a great help. Thanks.

Depending on how you execute the migration ( via sequelize-cli or programmatically via umzug ). There is a different way to expose the table via the ORM.
In your case you have queryInterface passed as an argument to your function. So you can do a "raw query" via the attached sequelize property.
up: function(queryInterface, Sequelize) {
return queryInterface.changeColumn('projects', 'status', {
type: Sequelize.ENUM('processing', 'unassigned', 'ongoing', 'completed'),
allowNull: false,
defaultValue: 'unassigned'
}).then(function() {
return queryInterface.sequelize
.query("UPDATE projects SET status='unassigned' WHERE status='processing'");
});
}
By doing this you will make a raw Query to your database.
You can check out this gist for more details on an advanced way of using the ORM inside the migration.
I'm a fan of using umzug programmatically, which executes the migrations and also provides the initialized models of your database. If you configure it properly, you will benefit the exposed models ( e.g. sequelize.model('project').update() ) and have a better looking code.

Sequelize: .createAssociation() or .setAssociation doesn't update the original object with created data

I've been stuck on this for a while. Take the following code as an example:
models.Summoner.findOne({
include: [{ model: models.RankedStats, as: 'SummonerRankedStats', required: true }],
where: { summonerId: summonerId, server: server }
}).then(function(summoner) {
models.RankedStats.create({
totalWins: 0,
totalLosses: 0
}).then(function(rankedStats) {
summoner.setSummonerRankedStats(rankedStats).then(function() {
console.log(summoner.SummonerRankedStats)
//This outputs undefined
summoner.getSummonerRankedStats().then(function(srs) {
console.log(srs)
//This outputs the RankedStats that were just created
})
models.Summoner.findOne({
include: [{ model: models.RankedStats, as: 'SummonerRankedStats', required: true }],
where: { summonerId: summonerId, server: server }
}).then(function(summoner) {
console.log(summoner.SummonerRankedStats)
//This outputs the SummonerRankedStats object
})
})
})
})
So, to put it simply... If I have a Summoner (var summoner) and perform a .setAssociation() or .createAssociation() on it, and then log summoner, the data created isn't there. If I fetch it again from the database (with .getAssociation() or by searching for that Summoner again) I can access it, but I was hoping to avoid that extra DB call.
Is there a way to add this information to the original object when using .create() or .set()? It can be achieved by doing something like:
summoner.dataValues.SummonerRankedStats = rankedStats
But that seems somewhat hacky :)
Is there a correct way to do it, or does it even make any sense?
Thanks in advance!

Meteor User table value axtracting

How do I pick the email address value from meteor Mongo user table?
I have written below query to pick the element:
users=Meteor.users.find({},{emails:1})
This the code I have written to fetch the email address, but I don't know how much it's affecting performance in the code:
users = Meteor.users.find({})
users.forEach(function(key,option){
key.emails.forEach(function (key,option){
console.log(key.address)
});
});

In meteor, you should call:
users = Meteor.users.find({}, { fields: { emails: 1 } })
Reference in docs
EDIT
Please remember users is a cursor object. Cursor objects can be handled directly in templates, and must be the return of publications. You can't iterate a cursor directly in a javascript loop.
Example: (remember authorization in production publications)
Meteor.publish('user-emails', function() {
return Meteor.users.find({}, { fields: { emails: 1 } });
});
If you want to directly access the user instances, for example to iterate them in a javascript code, you need to fetch the cursor (reference in docs).
Example:
var users = Meteor.users.find({}, { fields: { emails: 1 } }).fetch();
Now users is an array of users. Feel free to iterate them.
Example (I'm using underscore.js):
var users = Meteor.users.find({}, { fields: { emails: 1 } }).fetch();
_.each(users, function(user) {
console.log(user.emails);
});
Now, if you need a vector only with emails, one on each index, you can pluck the emails from a fetched array with underscore.js (reference of pluck)
var emails = _.pluck(Meteor.users.find({}, { fields: { emails: 1 } }).fetch(), 'emails');
Hope it works :)

if its not working, dont forget to return
return users