I want to do a category table that have a parent category by referencing the ObjectId from the same table.
Is it a normal practice or bad practice to refer ObjectId from the same table? If this is wrong, how do I go about it?
const CategorySchema = new Schema({
title: String,
description: String,
thumbnail: String,
image: String,
parentCategory: {
type: Schema.Types.ObjectId,
ref: 'category',
},
})
module.exports = mongoose.model('category', CategorySchema)
Related
If I update a field in collection B that is referenced by collection A, will collection A update too? Also vice versa?
collection A:
const userSchema = new mongoose.Schema({
email: String,
userName: String, //lets say I update username
password: String,
favoriteBooks: {
type: mongoose.Schema.Types.ObjectId,
ref: 'Book'
}
})
collection B:
const bookSchema = new mongoose.Schema({
name: String,
reviews: [String] //lets say I update or add review
})
If I update a subdocument:
collection A:
const userSchema = new mongoose.Schema({
email: String,
userName: String, //lets say I update username
password: String,
favoriteBooks: [BookSchema]
})
collection B:
const bookSchema = new mongoose.Schema({
name: String,
likesCount: Number
})
Thanks
After completing a course on MEAN Stack, I'm working on making my own webapp - a recipe page. I've designed my models, but when I try to fill the database with a new Recipe it just won't work. The main issue is the way I want to store ingredients, they'll be stored on one of the tables, then each recipe has its list of ingredients and amounts for each. For example, to make some toast you need, say "50 grs. of Butter and 4 slices of Bread". This is the Schema I'm using:
var RecipeSchema = Schema({
name: String,
desc: String,
author: { type: Schema.ObjectId, ref: 'User' },
category: { type: Schema.ObjectId, ref: 'Category' },
ingredients: [{ amount: String, ingredient: { type: Schema.ObjectId, ref: 'Ingredient' }}],
steps: [String],
image: String,
thumbnail: String,
portions: Number,
difficulty: Number,
cookingTime: Number,
comment: String
});
When I go in Postman and try to fill the "Toast Recipe" entry, I have the following:
name:Toast
desc:Toast is a common breakfast staple.
author:5cad791a7b2e651f7803f5de
category:5cb1ff8f484a172984178a97
ingredients:[{"amount": "4 slices", "ingredient": "5cb1ffdb484a172984178a98"}, {"amount": "35 grs.", "ingredient": "5cb2000d484a172984178a99"}]
steps:['Toast the bread in the oven.','Spread some butter on each toast.']
image:'null'
thumbnail:'null'
portions:1
difficulty:1
cookingTime:15
comment:'null'
But I keep getting a "cast Array" error. What could be the issue? Is it a problem with my model, with Postman, or with the way I'm sending the Array?
EDIT:
Apparently it was a problem whit the way I posted my arrays in Postman. After some more tests I managed to upload a full recipe in JSON format. The structure is correct (but what Juan suggests can be used too, to make the code cleaner).
I'am not completely sure, but when I worked with mongoose, inner objects had a new Schema object inside, in this case it would on ingredients
const IngredientSchema = new Schema({
amount: String,
ingredient: { type: Schema.ObjectId, ref:'Ingredient' }
});
const RecipeSchema = new Schema({
name: String,
desc: String,
author: { type: Schema.ObjectId, ref: 'User' },
category: { type: Schema.ObjectId, ref: 'Category' },
ingredients: [ IngredientSchema ],
steps: [String],
image: String,
thumbnail: String,
portions: Number,
difficulty: Number,
cookingTime: Number,
comment: String
});
this is what I have and it works:
var comboSchema = new Schema({
components: [{
type: Schema.Types.ObjectId,
ref: "Component"
}]
})
This is what I want to achieve:
var comboSchema = new Schema({
components: [{
type: Schema.Types.ObjectId,
ref: "Component",
amount: {type: Integer}
}]
})
Is it possible in MongoDB, if not what is the best workaround?
Thank you :-)
This schema work because of an element or filed name is provided
var comboSchema = new Schema({
components: [{
type: Schema.Types.ObjectId,
ref: "Component"
}]
})
Now you made a single mistak you want to create schema name without name in object with two different filed
Right way to create schema like this is to make other variable inside of array which contain type of filed
var comboSchema = new Schema({
components: [{
id: {
type: Schema.Types.ObjectId,
ref: "Component"
},
amount: { //If you want to make every component amount
type: Number
}
}]
})
Or
var comboSchema = new Schema({
amount: { type: Number },
//If you want to make only single amount on multiple components
components: [{
componentId: {
type: Schema.Types.ObjectId,
ref: "Component"
}
}]
})
But in both case you can't populate directly. You need to use aggregation for that to get data for embedded documents.
This is my user schema :
const userSchema = new Schema({
email: String,
username: String,
password: String,
secretToken: String,
active: Boolean,
type: String
}, {
timestamps: { // this will give us the detail when the account is created
createdAt: 'createdAt',
updatedAt: 'updatedAt'
}
});
this is my requirement Schema:
const requirementSchema = new Schema({
name: String,
age: String,
class: String,
subject: String,
email: String
}, {
timestamps: { // this will give us the detail when the requiremnt is created
createdAt: 'createdAt',
updatedAt: 'updatedAt'
}
});
how can I bring id from user schema to the requirement schema as secondary key?
I think mongodb is not meant for relationship. I could led to very bad practice if your database grow. But you can try https://docs.mongodb.com/manual/reference/database-references/#DatabaseReferences-DBRef for Database References.
There is no primary key foreign key concept in Mongodb. and normalization is also discouraged in mongodb.
In MongoDB, I have a One-To_many reference relationship.
A has many B.
A has a property called B_ids, so I can retrieve all the B instances owned by a a particular A instance.
My question is: looking to an instance of B, how can I retrieve the A instance that owns it?
Thanks!
In order to do that you can try this:
var personSchema = Schema({
_id: Schema.Types.ObjectId,
name: String,
age: Number,
stories: [{ type: Schema.Types.ObjectId, ref: 'Story' }]
});
var storySchema = Schema({
author: { type: Schema.Types.ObjectId, ref: 'Person' },
title: String,
fans: [{ type: Schema.Types.ObjectId, ref: 'Person' }]
});
in this way you can retrieve A from B using populate.
Story.find().populate('author')
Example borrowed from mongoose populate website.