I have an article table, where an article can cite multiple articles. Each article can also have a single author.
Article model :
class Article extends DefaultModel {
static get tableName() {
return "articles";
}
static get relationMappings() {
return {
author: {
relation: DefaultModel.BelongsToOneRelation,
modelClass: "Author",
join: {
from: "articles.authorId",
to: "authors.id"
}
},
mentions: {
relation: DefaultModel.ManyToManyRelation,
modelClass: "Article",
join: {
from: "articles.id",
through: {
from: "mentions.citingArticle",
to: "mentions.citedArticle"
},
to: "articles.id"
}
}
};
}
}
Mention model :
class Mention extends DefaultModel {
static get tableName() {
return "mentions";
}
static get idColumn() {
return ["citingArticle", "citedArticle"];
}
}
What I'm trying to do, is insertGraph, the main article + the articles that are mentioned in it, here is what I have :
async function insertData(fullArticle) {
const articleTx = await transaction(Article.knex(), async tx => {
const references = fullArticle.references
.map(articleObj => {
return {
...articleObj.article,
author: articleObj.author
};
});
const article = await Article.query(tx).insertGraph({
...fullArticle.article,
author: fullArticle.author,
mentions: references[0]
});
return article;
});
console.log(articleTx);
}
I know this is only inserting the main row + the first row, but I ran into multiple problems :
The mention model has a composite key, when I try to insert using the code above I get a (node:5944) UnhandledPromiseRejectionWarning: error: column "citedArticle" of relation "mentions" does not exist.
I also got the same error when I try to add "#id" to the main article mentions relation, and "#ref" to the cited article, and insert them in 2 different objects.
A third problem I ran into here, was a unique constraint on both the citing and the cited article authors. What if both of them were written by the same author? I have a unique string column in the authors table that isn't the id, when I tried to insert I got duplicate key value violates unique constraint "author_isn". I'm not sure how I can update the row to reference the existing author id if that happens.
Related
Hello. I can't figure out how to create multiple levels of nested queries with #ResolveFiled. I hope for your help. 🙏
What I'm doing and Context:
I have a product. The product has a supplier. A vendor-specific product contains product variants. Variants contain options.
I need to make a request in 4 levels:
Product
ProductHasProvider
Product Variants
Variant Options
I use the "Code First" approach, created an ObjectType for each entity. Next, I create a "Product" resolver.
Creating a second level "ProductHasProvider" with #ResolveField
When adding a ResolveField ("Providers") - it appears inside the main resolver "Product" and resolves the Providers ObjectType. Okay, it works, I can make requests at the 2nd level correctly.
#ResolveField('Providers', () => [ProductHasProvider])
async getProductProviders (#Parent() product: Product) {
const { id } = product;
return await this.productListService.ProductsProviders( { id });
}
I want to make third level where ProductHasProvider has Variants. I decorate ProductHasProvider as the parent.
#ResolveField(('variants'), type => [Variant])
async getVariants (#Parent() productHasProvider: ProductHasProvider) {
const { id } = productHasProvider;
return await this.productListService.getVariants({ id });
}
In this case, this ResolveField defines the ObjectType for [Variants], but for some reason at the first level. That is, in Apollo studio, the field is displayed in "Product". I can't query Variants for ProductHasProvider.
query Products {
getProducts {
Providers {
id
}
variants {
id
options {
id
}
}
}
}
Expected behavior:
I add a new #ResolveField(() => [Variants]) with "ProductHasProvider" parent (Which is already #ResorveField for Product). And I can do 3rd and 4th level queries.
query Products {
getProducts {
id
Providers {
id
variants {
id
options {
id
}
}
}
}
}
Please tell me what I'm doing wrong and how to achieve what I want. Thank you.🙏
#ResolveField is to be put in a Resolver, to specify how to return a specific field for a specific entity.
In your case, you have a Resolver for Products, in which you specify a #ResolveField for the field Providers.
I'm guessing that you are adding another #ResolveField in the same Resolver, and it will specify how to return another field of Products.
What you want is to create another Resolver, for Providers, in which you specify how to return the field variants.
Here is how it is working for me :
#Resolver('Product')
export class ProductsResolver {
#ResolveField('Providers', () => [ProductHasProvider])
async getProductProviders (#Parent() product: Product) {
const { id } = product;
return await this.productListService.ProductsProviders( { id });
}
}
#Resolver('Provider')
export class ProvidersResolver {
#ResolveField('variants', () => [Variant])
async getProductProviders (#Parent() provider: ProductHasProvider) {
const { id } = provider;
return await this.variantsService.getVariantForProvider( { id });
}
}
I am new to sequilizejs and basically am trying to refactor code that i've written in the controller and came across classMethods and instanceMethods. I see instance methods defined like so:
/lib/model/db/users.js
module.exports = function(sequelize, DataTypes) {
var instance_methods = get_instance_methods(sequelize);
var User = sequelize.define("User", {
email : {
type : DataTypes.STRING,
allowNull : false
},
}, {
classMethods: class_methods,
instanceMethods : instance_methods,
});
return User;
};
function get_instance_methods(sequelize) {
return {
is_my_password : function( password ) {
return sequelize.models.User.hashify_password( password ) === this.password;
},
};
function get_class_methods(sequelize) {
return {
hashify_password : function( password ) {
return crypto
.createHash('md5')
.update(
password + config.get('crypto_secret'),
(config.get('crypto_hash_encoding') || 'binary')
)
.digest('hex');
},
};
My understanding of the above is that classMethods are generic functions defined for the whole model and instanceMethods are basically a reference to a given row in a table/model, am i right in assuming this ? this would be my primary question.
Also i don't see any reference of classMethods and instanceMethods in the docs HERE. I only found this previous answer HERE. That provides a somewhat comprehensive understanding of the difference between instanceMethods and classMethods.
Basically i'am just trying to confirm weather my understanding matches the intended usage for class vs instance methods and also links to the official docs for the same would be highly appreciated.
The official way to add both static and instance methods is using classes like this:
class User extends Model {
static classLevelMethod() {
return 'foo';
}
instanceLevelMethod() {
return 'bar';
}
getFullname() {
return [this.firstname, this.lastname].join(' ');
}
}
User.init({
firstname: Sequelize.TEXT,
lastname: Sequelize.TEXT
}, { sequelize });
See Models as classes
Your understand is correct. In short: classes can have instances. Models are classes. So, Models can have instances. When working with an instance method, you will notice the this — which is the context, which refers to that particular class/model instance.
Hence, if you have a User model that has:
an instance method called is_my_password
a class model called hashify_password
User.hashify_password('123') will return the hashed version of 123. The User instance is not needed here. hashify_password is general function attached to the User model (class).
Now, if you'd like to call is_my_password() you do need a User instance:
User.findOne({...}).then(function (user) {
if (user.is_my_password('123')) {
// ^ Here we call `is_my_password` as a method of the user instance.
...
}
}).catch(console.error)
In general, when you have functions that do not need the particular model instance data, you will define them as class methods. They are static methods.
And when the function works with the instance data, you define it as instance method to make it easier and nicer to call.
I am using nest.js and TypeORM. I need to make a query that returns all the rows from a table, where facility_id equals some value, and date is less than or equal to (<=) some date value.
I read the documentation about nest.js, and I couldn't find a proper way to do it.
Also, I read the official GitHub documentation for typeORM.
Here is my code. It would be great if it could be done with find method from EntityRepository
import { DeleteResult, EntityRepository, Repository, UpdateResult } from "typeorm";
import { Reservations} from "src/Entities/reservations.entity";
import { Facility} from "src/Entities/facility.entity";
import { PaginationParams } from "src/pagination.model";
import { LessThanOrEqual } from "typeorm";
#EntityRepository(Reservation)
export class ReservationRepository extends Repository<Reservation> {
async findByFacility(ustanovaId, paginationParams, dateParams): Promise<Reservation[]> {
return await this.find({where: { termin: LessThanOrEqual(new Date(2021, 0, 1))},
relations: ["users", "facility"],
take: paginationParams.limit,
skip: paginationParams.offset,
order: {
[paginationParams.orderby]: paginationParams.order.toUpperCase()
}});
}
}
Since you haven't given the proper information about Reservation and Facility entities, I am guessing two possible scenarios (usually both the scenarios will be true). You can select the code solution from either.
1. Reservation entity has a facility_id column
const facilityId = "YourFacilityID";
return this.find({
where: {
termin: LessThanOrEqual(new Date(2021, 0, 1)),
facility_id: facilityId
},
relations: ["users", "facility"],
take: paginationParams.limit,
skip: paginationParams.offset,
order: {
[paginationParams.orderby]: paginationParams.order.toUpperCase()
}
});
2. Reservation entity has facility reference
Reservation entity has an OneToOne or ManyToOne relationship with Facility entity where the relationship is named facility and Facility entity has id which is equal to facility_id you explained in the question.
const facilityId = "YourFacilityID";
return this.find({
where: {
termin: LessThanOrEqual(new Date(2021, 0, 1)),
facility: { id: facilityId }
},
relations: ["users", "facility"],
take: paginationParams.limit,
skip: paginationParams.offset,
order: {
[paginationParams.orderby]: paginationParams.order.toUpperCase()
}
});
Also, return await is actually redundant and you can always replace it with just return.
Hope this helps. Cheers! 🍻
How do you write the schema and query for nested foreign keys? I checked the docs and found no examples of how to do this. So here was my attempt based on github and stackoverflow answers lets say I have these models:
class Address(models.Model):
name = models.CharField()
class Person(models.Model):
name = models.CharField()
address = models.ForeignKey('Address', on_delete=models.CASCADE, blank=False, null=False)
class Blog(models.Model):
person = models.ForeignKey('Person', on_delete=models.CASCADE, blank=False, null=False)
text = models.TextField()
I tried writing a schema like this:
class AddressInput(graphene.InputObjectType):
name = graphene.String(required=True)
class PersonInput(graphene.InputObjectType):
name = graphene.String(required=True)
address =graphene.Field(AddressInput)
class CreateNewBlog(graphene.Mutation):
blog=graphene.Field(BlogType)
class Arguments:
address_data = AddressInput()
person_data = PersonInput()
text = graphene.String()
#staticmethod
def mutate(root, info, person_data=None, address_data=None, **input):
address = Address.objects.create(name=address_data.name)
person = Person.objects.create(address=address, name=person_data.name)
blog = Blog.objects.create(person =person, text=input['text'])
blog.save()
return CreateNewBlog(blog=blog)
and I used a query like this:
mutation {
CreateNewBlog(person: { address: {name: "aaa"},
name: "First Last" }, text: "hi hi") {
Blog {
person{
name
address{
name
}
},
text
}
}
}
I got this error message:
{
"errors": [
{
"message": "'NoneType' object has no attribute 'name'",
"locations": [
{
"line": 32,
"column": 9
}
],
"path": [
"CreateNewBlog"
]
}
],
"data": {
"CreateNewBlog": null
}
}
I think the issue is in the way I wrote the schema.py file. Where it does not work to nest InputFields inside another InputField. Is there any other ways to write a single mutation?
Okay, a few things here. Firstly, you should generate your schema.graphql file, because that'll show you the actual final shape of the schema being built by Graphene, which would've made your debugging easier. Or you could use GraphiQL to test out your queries and lets its documentation and autocomplete do the heavy lifting for you.
But on to the specifics, your Graphene mutation definition is going to be generating a mutation that looks like this:
input AddressInput {
name: String!
}
input PersonInput {
name: String!
address: AddressInput
}
type CreateNewBlogOutput {
blog: Blog
}
type Mutation {
CreateNewBlog(addressData: AddressInput, personData: PersonInput, text: String): CreateNewBlogOutput!
}
Worth noting that there are two ways for you to supply an AddressInput here, one at root, and one inside PersonInput. This probably isn't what you're intending to do. Secondly, none of the root arguments are required, which is contributing to your error message being fairly unhelpful, because the problem is you're calling the mutation incorrect parameters but the query validator is letting it through because your types are very permissive.
I believe that if you were to run the mutation like the following, it'd actually work:
mutation {
CreateNewBlog(
personData: {
address: {
name: "aaa"
},
name: "First Last"
},
text: "hi hi"
) {
blog {
person {
name
address {
name
}
}
text
}
}
}
I only made two changes here, person was changed to personData (to match your mutation definition, Graphene does the conversation from snake case to camel case automatically), and Blog to blog in the field selection.
But lets go a little further, here's how I would have made the mutation.
class AddressInput(graphene.InputObjectType):
name = graphene.String(required=True)
class PersonInput(graphene.InputObjectType):
name = graphene.String(required=True)
address = AddressInput(required=True)
class CreateNewBlogInput(graphene.InputObjectType):
person = PersonInput(required=True)
text = graphene.String(required=True)
class CreateNewBlogPayload(graphene.ObjectType):
blog = graphene.Field(BlogType, required=True)
class CreateNewBlog(graphene.Mutation):
class Arguments:
input_data = CreateNewBlogInput(required=True, name="input")
Output = CreateNewBlogPayload
#staticmethod
def mutate(root, info, input_data):
address = Address.objects.create(name=input_data.person.address.name)
person = Person.objects.create(address=address, name=input_data.person.name)
blog = Blog.objects.create(person=person, text=input_data.text)
blog.save()
return CreateNewBlogPayload(blog=blog)
I'd also change CreateNewBlog to createNewBlog when constructing Graphene's mutation object, because the GraphQL convention is to use lower camel case for mutations.
Then you'd run it like this:
mutation {
createNewBlog(
input: {
person: {
address: {
name: "aaa"
},
name: "First Last"
}
text: "hi hi"
}
) {
blog {
person {
name
address {
name
}
}
text
}
}
}
Why wrap the entire input in a single input field? Mainly because it makes calling the mutation easier in the client when using variables, you can just provide single input arg of the correct shape rather than multiple.
// So instead of this
mutation OldCreateNewBlog($person: PersonInput, $text: String) {
createNewBlog(
personData: $person
text: $text
) {
blog {
person {
name
address {
name
}
}
text
}
}
}
// You have this
mutation NewCreateNewBlog($input: CreateNewBlogInput!) {
createNewBlog(
input: $input
) {
blog {
person {
name
address {
name
}
}
text
}
}
}
The latter makes it easier to change the input shape over time and only have to make the change in one place in client code.
I am new to node.js and newer to Sails.js framework.
I am currently trying to work with my database, I don't understand all the things with Sails.js but I manage to do what I want step by step. (I am used to some PHP MVC frameworks so it is not too difficult to understand the structure.)
Here I am trying to get a row from my database, using 2 JOIN clause. I managed to do this using SQL and the Model.query() function, but I would like to do this in a "cleaner" way.
So I have 3 tables in my database: meta, lang and meta_lang. It's quite simple and a picture being better than words, here are some screenshots.
meta
lang
meta_lang
What I want to do is to get the row in meta_table that match with 'default' meta and 'en' lang (for example).
Here are Meta and Lang models (I created them with sails generate model command and edited them with what I needed):
Meta
module.exports = {
attributes: {
code : { type: 'string' },
metaLangs:{
collection: 'MetaLang',
via: 'meta'
}
}
};
Lang
module.exports = {
attributes: {
code : { type: 'string' },
metaLangs:{
collection: 'MetaLang',
via: 'lang'
}
}
};
And here is my MetaLang model, with 3 functions I created to test several methods. The first function, findCurrent, works perfectly, but as you can see I had to write SQL. That is what I want to avoid if it is possible, I find it more clean (and I would like to use Sails.js tools as often as I can).
module.exports = {
tableName: 'meta_lang',
attributes: {
title : { type: 'string' },
description : { type: 'text' },
keywords : { type: 'string' },
meta:{
model:'Meta',
columnName: 'meta_id'
},
lang:{
model:'Lang',
columnName: 'lang_id'
}
},
findCurrent: function (metaCode, langCode) {
var query = 'SELECT ml.* FROM meta_lang ml INNER JOIN meta m ON m.id = ml.meta_id INNER JOIN lang l ON l.id = ml.lang_id WHERE m.code = ? AND l.code = ?';
MetaLang.query(query, [metaCode, langCode], function(err, metaLang) {
console.log('findCurrent');
if (err) return console.log(err);
console.log(metaLang);
// OK this works exactly as I want (I would have prefered a 'findOne' result, only 1 object instead of an array with 1 object in it, but I can do with it.)
});
},
findCurrentTest: function (metaCode, langCode) {
Meta.findByCode(metaCode).populate('metaLangs').exec(function(err, metaLang) {
console.log('findCurrentTest');
if (err) return console.log(err);
console.log(metaLang);
// I get what I expected (though not what I want): my meta + all metaLangs related to meta with code "default".
// What I want is to get ONE metaLang related to meta with code "default" AND lang with code "en".
});
},
findCurrentOthertest: function (metaCode, langCode) {
MetaLang.find().populate('meta', {where: {code:metaCode}}).populate('lang', {where: {code:langCode}}).exec(function(err, metaLang) {
console.log('findCurrentOthertest');
if (err) return console.log(err);
console.log(metaLang);
// Doesn't work as I wanted: it gets ALL the metaLang rows.
});
}
};
I also tried to first get my Meta by code, then my Lang by code, and MetaLang using Meta.id and Lang.id . But I would like to avoid 3 queries when I can have only one.
What I'm looking for would be something like MetaLang.find({meta.code:"default", lang.code:"en"}).
Hope you've got all needed details, just comment and ask for more if you don't.
Do you know what populate is for ? its for including the whole associated object when loading it from the database. Its practically the join you are trying to do, if all you need is row retrieval than quering the table without populate will make both functions you built work.
To me it looks like you are re-writing how Sails did the association. Id suggest giving the Associations docs another read in Sails documentation: Associations. As depending on your case you are just trying a one-to-many association with each table, you could avoid a middle table in my guess, but to decide better id need to understand your use-case.
When I saw the mySQL code it seemed to me you are still thinking in MySQL and PHP which takes time to convert from :) forcing the joins and middle tables yourself, redoing a lot of the stuff sails automated for you. I redone your example on 'disk' adapter and it worked perfectly. The whole point of WaterlineORM is to abstract the layer of going down to SQL unless absolutely necessary. Here is what I would do for your example, first without SQL just on a disk adapter id create the models :
// Lang.js
attributes: {
id :{ type: "Integer" , autoIncrement : true, primaryKey: true },
code :"string"
}
you see what i did redundantly here ? I did not really need the Id part as Sails does it for me. Just an example.
// Meta.js
attributes: {
code :"string"
}
better :) ?
// MetaLang.js
attributes:
{
title : "string",
desc : "string",
meta_id :
{
model : "meta",
},
lang_id :
{
model : "lang",
}
}
Now after simply creating the same values as your example i run sails console type :
MetaLang.find({meta_id : 1 ,lang_id:2}).exec(function(er,res){
console.log(res);
});
Output >>>
sails> [ { meta_id: 1,
lang_id: 2,
title: 'My blog',
id: 2 } ]
Now if you want to display what is meta with id 1 and what is lang with id 2, we use populate, but the referencing for join/search is just as simple as this.
sails> Meta_lang.find({meta_id : 1 ,lang_id:2}).populate('lang_id').populate('meta_id').exec(function(er,res){ console.log(res); });
undefined
sails> [ {
meta_id:
{ code: 'default',
id: 1 },
lang_id:
{ code: 'En',
id: 2 },
title: 'My blog',
id: 2 } ]
At this point, id switch adapters to MySQL and then create the MySQL tables with the same column names as above. Create the FK_constraints and voila.
Another strict policy you can add is to set up the 'via' and dominance on each model. you can read more about that in the Association documentation and it depends on the nature of association (many-to-many etc.)
To get the same result without knowing the Ids before-hand :
sails> Meta.findOne({code : "default"}).exec(function(err,needed_meta){
..... Lang.findOne({code : "En"}).exec(function(err_lang,needed_lang){
....... Meta_lang.find({meta_id : needed_meta.id , lang_id : needed_lang.id}).exec(function(err_all,result){
......... console.log(result);});
....... });
..... });
undefined
sails> [ { meta_id: 1,
lang_id: 2,
title: 'My blog',
id: 2 } ]
Have you tried:
findCurrentTest: function (metaCode, langCode) {
Meta.findByCode(metaCode).populate('metaLangs', {where: {code:langCode}}).exec(function(err, metaLang) {
console.log('findCurrentTest');
if (err) return console.log(err);
console.log(metaLang);
});
},