I have a query I'm trying to perform based on a one to many relationship.
As an example there is a model called Users and one called Projects.
Users hasMany Projects
Projects have many types which are stored in a type (enum) column. There are 4 different types that potentially a user may have that I want to load. The catch is I want to include the most recent project record (createdAt column) for all networks that potentially will be there. I have not found a way to structure the query for it to work as an include. I have however found a way to do a raw query which does what I want.
I am looking for a way without having to do a raw query. By doing the raw query I have to map the returned results to users I've returned from the other method, or I have to do a simple include and then trim off all the results that are not the most recent. The latter is fine, but I see this getting slower as a user will have many projects and it will keep growing steadily.
This allow serialize a json for anywhere action about a model. Read it, very well
sequelize-virtual-fields
// define models
var Person = sequelize.define('Person', { name: Sequelize.STRING });
var Task = sequelize.define('Task', {
name: Sequelize.STRING,
nameWithPerson: {
type: Sequelize.VIRTUAL,
get: function() { return this.name + ' (' + this.Person.name + ')' }
attributes: [ 'name' ],
include: [ { model: Person, attributes: [ 'name' ] } ],
order: [ ['name'], [ Person, 'name' ] ]
}
});
// define associations
Task.belongsTo(Person);
Person.hasMany(Task);
// activate virtual fields functionality
sequelize.initVirtualFields();
Related
I need to create a database of shopify orders so I can run advanced queries and sales reports that you can't do in the shopify admin area. I'm building in Sails .12 and mysql. Shopify lets you register a webhook so that every time an order is placed, it creates a POST to the specified URL with the order data in the body as JSON. The products ordered are an array of JSON objects as one of the values in the POST:
{
"id": 123456,
"email": "jon#doe.ca",
"created_at": "2017-01-10T14:26:25-05:00",
...//many more entires
"line_items": [
{
"id": 24361829895,
"variant_id": 12345,
"title": "T-Shirt",
"quantity": 1,
"price": "140.00",
},
{
"id": 44361829895,
"variant_id": 42345,
"title": "Hat",
"quantity": 1,
"price": "40.00",
},
]
}
I need to save the order into an Orders table, and the products ordered into a line_items table that is a one to many relation; one order can have many line_items (products ordered). There are over 100 key-value pairs sent by the webhook, and I'm saving all of it. I've created my two models where I define the data type, so now i have very long Order.js and Line_item.js files, and I'm using the
line_items: {
collection: 'line_item',
via: 'order_id'
},
in my Order.js, and
order_id: {
model: 'order'
},
in my Line_item.js models to relate them. Is this the correct way to denfine my two tables? Also, where would I put the code that maps the JSON to the model parameters? If I put that code in the controllers, would I have to type another 100+ lines of code to map each json value to its correct parameter. The how would I save to the two different models/tables? Eg:
var newOrder = {};
newOrder.id =req.param('id');
newOrder.email = req.param('email');
newOrder.name = req.param('name');
...//over 100 lines more, then Order.create(newOrder, ...)
var newLine_items = req.params('line_items'); //an array
_.forEach(newLine_items, function(line_item){
var newLine_item = {};
newLine_item.id = line_item.id;
newLine_item.order_id = newOrder.id;
newLine_item.title = line_item.title;
//etc for over 20 more lines, then Line_item.create(newLine_item, ...)
});
I need to save the order into an Orders table, and the products ordered into a line_items table that is a one to many relation; one order can have many line_items (products ordered).
That sounds completely reasonable, well, besides the use of the Oxford comma :)
There are over 100 key-value pairs sent by the webhook
I'm not sure that I understand exactly what this is or what it is used for within this process.
That being said, it might help to have a single attribute in your model for this which has a JSON value, then retrieve and work with it as JSON instead of trying to manually account for each attribute if that is what you're doing over there?
It really depends on your use case and how you'll use the data though but I figure if the format changes you might have a problem, not so if it's just being stored and parsed as a JSON object?
Also, where would I put the code that maps the JSON to the model parameters
In v0.12.x take a look at Services.
In v1, Services will still work but moving this logic into Helpers might be a good option but then, it seems that a custom model method would be a better one.
Here is a shorter version of your code:
var newOrder = req.allParams();
newLine_items = {};
_.forEach(newOrder.line_items, function(line_item) {
newLine_items.push(line_item);
});
Here is what your logic might look like:
var newOrder = req.allParams();
// Store the order
Order
.create(newOrders)
.exec(function (err, result) {
if (err) // handle the error
var newLine_items = {};
_.forEach(newOrder.line_items, function(line_item) {
// Add the order id for association
line_item.order_id = result.id;
// Add the new line item with the orders id
newLine_items.push(line_item);
});
// Store the orders line items
LineItems
.create(newLine_items)
.exec(function (err, result) {
if (err) // handle the error
// Handle success
});
});
And the lifecycle callback in the Order model:
beforeCreate: function (values, cb) {
delete(values.line_items);
cb();
}
But you really should look into bluebird promises as the model methods in version one of sails have opt in support for them and it helps to negate the pyramid of doom that is starting in my example and is also something that you want to avoid :P
I have the following scenario, my application has two entities: box and items with N to N relationship. I am using sequelize with MySQL.
I am using pseudocode to represent the tables:
Box {
id: Integer primary key
name: String
}
Item {
id: Integer primary key
name: String
}
I have set up the schemas with relations hasMany in both directions using the following through relation:
Box.hasMany(Item, { through: Box_Item });
Item.hasMany(Box, { through: Box_Item });
Box_Item {
id_box: Integer,
id_item: Integer,
item_order: Integer
}
With primary_key(id_box, id_item).
I tested it and I can call myBox.getItems() on my instance object myBox and easily get all the items it has.
I can make calls as
BoxModel.findOne({
where: { id: 1 },
include: [{ model: ItemModel }]
});
And it automatically understands there is a relation between the models through Box_Item and get everything correctly, except that I'm not getting the results sorted by item_order field. This field is a number from 1 to N that represents the item order inside that box.
I tried
BoxModel.findOne({
where: { id: 1 },
include: [
{
model: ItemModel,
order: 'item_order'
}
]
});
But it seems sequelizejs does not support order inside include yet (checked on their github repo).
I tried to force
BoxModel.findOne({
where: { id: 1 },
order: '`box_model`.`item_order`'
include: [ { model: ItemModel } ]
})
looking through the query sequelize creates but it just put the ORDER BY in two different places (inside INNER JOIN and at the end of the query, don't know why...) and I got an error.
So I searched for this on stackoverflow (1), found a few questions but I don't get a good way for doing that using the ORM.
How could I get the items sorted by item_order field when asking for specific box items?
After a few days trying to get it done I found an answer on stackoverflow that helped me.
After creating the relationships between Box and Item I can easily call on an instance:
myBox.getItems({
order: '`box_model`.`item_order`'
});
And then I get the result I'm expecting. But I had to look through the query sequelize is creating based on the models and get the correct field based on their renaming rules.
If you want you can pass the as parameter and rename your tables.
Using sails 0.10.5/waterline 0.10.15:
I cannot find an answer to a simple question: how to count the elements of an association without using populate() (which would load all data).
Let take a simple many2many relation with via:
User:
attributes: {
following: {
collection: 'user',
via: 'follower',
dominant: true
},
follower: {
collection: 'user',
via: 'following'
}
Now I need the size of the collections.
Currently I try
User.findById(1).populateAll().exec(function(err, user) {
// count of followings -> user.following.length;
// count of followers-> user.follower.length;
}
which leads to loading the collections.
I'm missing a count function at collection level to avoid population/loading of data.
Is there a possibility to access the (auto generated) join tables to run a count-query directly on the join?
Something like:
User.findById(1).count({'followings'}).exec(function(err, followings) {
...}
or
UserFollowingFollow_FollowFollowing.countByUserFollowingFollowId(1).
exec(function(err, followings) {
...}
Waterline does offer the count query method and it can be used like this to solve your problem:
User.count().where({follower: followerId})
.exec(function(err, numberOfFollowings) {
//numberOfFollowings will be the integer that you need
})
followerId is the id that you are passing to User.findOne() in your example.
You can also read the Waterline documentation about this.
Please share your experience with partial updating of JSON document.At now I'm storing my JSON documents in MongoDB which looks like the following:
{
id: ObjectId(507f191e810c19729de860ea),
title: 'Sterling Archer',
comments: [
{text: 'Comment text', tags: ['tag1', 'tag2', 'tag3']},
{text: 'Comment test', tags: ['tag2', 'tag5']}
]
}
I need to frequently update my documents by using rfc6902 specification. Now, I do it not optimized way that looks the following (I use nodejs/express/mongoose and fast-json-patch module in this example):
var jsonpatch = require('fast-json-patch');
app.patch('/document/:id', function (req, res, next) {
var document_id = req.params.id;
// req.body.patch: { "op": "add", "path": "/comments/2", "value": {text: 'Comment test3', tags: ['tag4']}" }
var patches = req.body.patch;
// find document
Document.findById(document_id, function (err, document) {
// Applying patches
jsonpatch.apply(document, patches);
// Update whole document in MongoDB
Document.update({_id: document_id}, document, function (err) {
return res.status(200).send();
});
});
});
This is not optimize approach to patch documents due two queries in MongoDB and replacing whole document. So I'm looking for optimized approach and want to try RethinkDB for this task. Can you help me to inspect possibility of atomic document updating by using single query with RethinkDB? Or should I looks for another way of resolving my problem?
Please share your experience with partial updating of JSON document.
You just need one query in RethinkDB. Suppose you want to update the document whose id is 1 with the values {foo: 1, bar: 2}, and increment the field "count", you would do
r.table("data").get(1).update(function(doc) {
return doc.merge({foo: 1, bar:2, count: doc("count").add(1) })
})
While this update requires a unique query, the whole document will be updated.
If you have big documents, you can split them in multiple tables and perform joins later to retrieve the data.
You may be interested in reading this article about data modeling: http://www.rethinkdb.com/docs/data-modeling/
Alright so I have a project in NodeJS where I'm utilizing Sequelize for a MySQL ORM. The thing works fantastically however I'm trying to figure out if there is a way to specify what fields are being returned on a query basis or if there's even a way just to do a .query() somewhere.
For example in our user database there can be ridiculous amounts of records and columns. In this case I need to return three columns only so it would be faster to get just those columns. However, Sequelize just queries the table for everything "*" to fulfill the full object model as much as possible. This is the functionality I'd like to bypass in this particular area of the application.
You have to specify the attributes as a property in the object that you pass to findAll():
Project.findAll({attributes: ['name', 'age']}).on('success', function (projects) {
console.log(projects);
});
How I found this:
The query is first called here: https://github.com/sdepold/sequelize/blob/master/lib/model-definition.js#L131
Then gets constructed here: https://github.com/sdepold/sequelize/blob/master/lib/connectors/mysql/query-generator.js#L56-59
Try this in new version
template.findAll({
where: {
user_id: req.params.user_id
},
attributes: ['id', 'template_name'],
}).then(function (list) {
res.status(200).json(list);
})
Use the arrays in the attribute key. You can do nested arrays for aliases.
Project.findAll({
attributes: ['id', ['name', 'project_name']],
where: {id: req.params.id}
})
.then(function(projects) {
res.json(projects);
})
Will yield:
SELECT id, name AS project_name FROM projects WHERE id = ...;
All Answers are correct but we can also use include and exclude as well
Model.findAll({
attributes: { include: ['id'] }
});
Model.findAll({
attributes: { exclude: ['createdAt'] }
});
Source