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here is the code for query builder in mongoose .
QueryBuiders are very important in mongoose because you can build queries inside QueryBuilders and define any type of query as per your requirement.
You can call these querybuilders multiple times as much you need it . But if you do not create your own query builder then you have to write that query each time whenever you need that query.
QueryBuilder helps you to write efficient code and make your program better
const mongoose = require('mongoose');
main().catch(err => console.log(err));
async function main() {
await mongoose.connect('mongodb://127.0.0.1:27017/AnimalData');
const animalSchema = new mongoose.Schema({
name: String,
breed: String,
price : Number,
discPerc : Number,
discAvailable : Boolean,
CountryOrigin : String,
},
{
query: {
// findByName query is here
async byName(name) {
console.log("Out of query builder function()....");
const resAnimal = await this.where("name").equals(name);
console.log("all the animals of name = "+name+" is found "+resAnimal.length);
console.log(resAnimal);
for(var i = 0; i < resAnimal.length; i++){
console.log("name of the animaal = "+resAnimal[i].name);
console.log("breed of the animaal = "+resAnimal[i].breed);
console.log("price of the animaal = "+resAnimal[i].price);
console.log("discPerc of the animaal = "+resAnimal[i].discPerc);
console.log("discAvailable of the animaal = "+resAnimal[i].discAvailable);
console.log("CountryOrigin of the animaal = "+resAnimal[i].CountryOrigin);
}
return resAnimal;
},
// findByPrice query is here
async byPrice(min, max) {
console.log("Out of query builder function()....");
//await Tank.find({ size: 'small' }).where('createdDate').gt(oneYearAgo).exec();
const resAnimal = await this.where("price").gte(min).lte(max);
console.log("all the animals of price between = $"+min+" and $"+max+" is found "+resAnimal.length);
console.log(resAnimal);
for(var i = 0; i < resAnimal.length; i++){
console.log("name of the animal = "+resAnimal[i].name);
console.log("breed of the animal = "+resAnimal[i].breed);
console.log("price of the animal = "+resAnimal[i].price);
console.log("discPerc of the animal = "+resAnimal[i].discPerc);
console.log("discAvailable of the animal = "+resAnimal[i].discAvailable);
console.log("CountryOrigin of the animal = "+resAnimal[i].CountryOrigin);
if(resAnimal[i].discAvailable){
const netPrice = resAnimal[i].price - resAnimal[i].price * (resAnimal[i].discPerc / 100);
console.log("\nprice after discount = $"+netPrice);
}
else{
console.log("\nDiscount is not available...for : "+resAnimal[i].name);
}
}
return resAnimal;
},
}
});
animalSchema.query.byBreed = async function(animal_breed) {
console.log("byBreed function is executing...");
const resAnimal = await this.where('breed').equals(animal_breed);
console.log("all the breed of : "+animal_breed+", found = "+resAnimal.length+" times..");
for(var i = 0; i < resAnimal.length; i++){
console.log("\nname of the animal : "+resAnimal[i].name);
console.log("breed of the animal : "+resAnimal[i].breed);
console.log("price of the animal : $"+resAnimal[i].price);
console.log("discPerc of the animal : "+resAnimal[i].discPerc+" '%' ");
console.log("discAvailable of the animal : "+resAnimal[i].discAvailable);
console.log("CountryOrigin of the animal : "+resAnimal[i].CountryOrigin);
}
return resAnimal;
};
const Animal = mongoose.model('Animal', animalSchema);
await Animal.insertMany([
{
name: "Agean",
breed: "Cat",
price : 240,
discPerc : 16,
discAvailable : true,
CountryOrigin : "Greece",
},
{
name: "American Bobtail",
breed: "Cat",
price : 355,
discPerc : 23,
discAvailable : true,
CountryOrigin : "United States",
},
{
name: "Common KeelBack",
breed: "Snake",
price : 157,
discPerc : 34,
discAvailable : false,
CountryOrigin : "New Guinea",
},
{
name: "Glosy Snake",
breed: "Snake",
price : 497,
discPerc : 29,
discAvailable : false,
CountryOrigin : "Mexico",
},
{
name: "Philippine forest rat",
breed: "Rat",
price : 179,
discPerc : 7,
discAvailable : true,
CountryOrigin : "Philippines",
},
{
name: "Rare UniBack",
breed: "Rat",
price : 88,
discPerc : 13,
discAvailable : false,
CountryOrigin : "New Guinea",
},
]);
const animals = await Animal.find({});
console.log(animals);
const nameResult = await Animal.find().byName('Glosy Snake');
console.log(nameResult);
const breedResult = await Animal.find().byBreed("Rat");
console.log(breedResult);
const priceResult = await Animal.find().byPrice(100, 200);
console.log(priceResult);
}
Here we have created byName(), byPrice(), byBreed() these three query builder . Among these three queryBuilders only one is outside the schema , i.e : byBreed() . byName() and byPrice() are built inside schema . Now checkout the output :
PS C:\Users\USER\Downloads\mongoExpress\SchemaModel_QueryBuilders> node src/queryBuilder_1.js
[
{
_id: new ObjectId('65c4fdcc73ad7f090cd8cd0d'),
name: 'Siberian Husky',
breed: 'Dog',
countryOrigin: 'Siberia',
__v: 0
},
{
_id: new ObjectId('65c4fdcc73ad7f090cd8cd0e'),
name: 'British Smooth Hair',
breed: 'Cat',
countryOrigin: 'United Kingdom',
__v: 0
},
{
_id: new ObjectId('65c4fdcc73ad7f090cd8cd0f'),
name: 'American Short Hair',
breed: 'Cat',
countryOrigin: 'USA',
__v: 0
},
{
_id: new ObjectId('65c4fdcc73ad7f090cd8cd10'),
name: 'Bull Dog',
breed: 'Dog',
countryOrigin: 'Switzerland',
__v: 0
},
{
_id: new ObjectId('65c500ee9a015a02983f3dd9'),
name: 'Agean',
breed: 'Cat',
price: 240,
discPerc: 16,
discAvailable: true,
CountryOrigin: 'Greece',
__v: 0
},
{
_id: new ObjectId('65c500ee9a015a02983f3dda'),
name: 'American Bobtail',
breed: 'Cat',
price: 355,
discPerc: 23,
discAvailable: true,
CountryOrigin: 'United States',
__v: 0
},
{
_id: new ObjectId('65c500ee9a015a02983f3ddb'),
name: 'Common KeelBack',
breed: 'Snake',
price: 157,
discPerc: 34,
discAvailable: false,
CountryOrigin: 'New Guinea',
__v: 0
},
{
_id: new ObjectId('65c500ee9a015a02983f3ddc'),
name: 'Glosy Snake',
breed: 'Snake',
price: 497,
discPerc: 29,
discAvailable: false,
CountryOrigin: 'Mexico',
__v: 0
},
{
_id: new ObjectId('65c500ee9a015a02983f3ddd'),
name: 'Philippine forest rat',
breed: 'Rat',
price: 179,
discPerc: 7,
discAvailable: true,
CountryOrigin: 'Philippines',
__v: 0
},
{
_id: new ObjectId('65c500ee9a015a02983f3dde'),
name: 'Rare UniBack',
breed: 'Rat',
price: 88,
discPerc: 13,
discAvailable: false,
CountryOrigin: 'New Guinea',
__v: 0
}
]
Out of query builder function()....
all the animals of name = Glosy Snake is found 1
[
{
_id: new ObjectId('65c500ee9a015a02983f3ddc'),
name: 'Glosy Snake',
breed: 'Snake',
price: 497,
discPerc: 29,
discAvailable: false,
CountryOrigin: 'Mexico',
__v: 0
}
]
name of the animaal = Glosy Snake
breed of the animaal = Snake
price of the animaal = 497
discPerc of the animaal = 29
discAvailable of the animaal = false
CountryOrigin of the animaal = Mexico
[
{
_id: new ObjectId('65c500ee9a015a02983f3ddc'),
name: 'Glosy Snake',
breed: 'Snake',
price: 497,
discPerc: 29,
discAvailable: false,
CountryOrigin: 'Mexico',
__v: 0
}
]
byBreed function is executing...
all the breed of : Rat, found = 2 times..
name of the animal : Philippine forest rat
breed of the animal : Rat
price of the animal : $179
discPerc of the animal : 7 '%'
discAvailable of the animal : true
CountryOrigin of the animal : Philippines
name of the animal : Rare UniBack
breed of the animal : Rat
price of the animal : $88
discPerc of the animal : 13 '%'
discAvailable of the animal : false
CountryOrigin of the animal : New Guinea
[
{
_id: new ObjectId('65c500ee9a015a02983f3ddd'),
name: 'Philippine forest rat',
breed: 'Rat',
price: 179,
discPerc: 7,
discAvailable: true,
CountryOrigin: 'Philippines',
__v: 0
},
{
_id: new ObjectId('65c500ee9a015a02983f3dde'),
name: 'Rare UniBack',
breed: 'Rat',
price: 88,
discPerc: 13,
discAvailable: false,
CountryOrigin: 'New Guinea',
__v: 0
}
]
Out of query builder function()....
all the animals of price between = $100 and $200 is found 2
[
{
_id: new ObjectId('65c500ee9a015a02983f3ddb'),
name: 'Common KeelBack',
breed: 'Snake',
price: 157,
discPerc: 34,
discAvailable: false,
CountryOrigin: 'New Guinea',
__v: 0
},
{
_id: new ObjectId('65c500ee9a015a02983f3ddd'),
name: 'Philippine forest rat',
breed: 'Rat',
price: 179,
discPerc: 7,
discAvailable: true,
CountryOrigin: 'Philippines',
__v: 0
}
]
name of the animal = Common KeelBack
breed of the animal = Snake
price of the animal = 157
discPerc of the animal = 34
discAvailable of the animal = false
CountryOrigin of the animal = New Guinea
Discount is not available...for : Common KeelBack
name of the animal = Philippine forest rat
breed of the animal = Rat
price of the animal = 179
discPerc of the animal = 7
discAvailable of the animal = true
CountryOrigin of the animal = Philippines
price after discount = $166.47
[
{
_id: new ObjectId('65c500ee9a015a02983f3ddb'),
name: 'Common KeelBack',
breed: 'Snake',
price: 157,
discPerc: 34,
discAvailable: false,
CountryOrigin: 'New Guinea',
__v: 0
},
{
_id: new ObjectId('65c500ee9a015a02983f3ddd'),
name: 'Philippine forest rat',
breed: 'Rat',
price: 179,
discPerc: 7,
discAvailable: true,
CountryOrigin: 'Philippines',
__v: 0
}
]
Top comments (1)
If any one face any problem to understand this code please let me know