1) Alias is a very important concept for those who want to master mongoose .
2) Alias provides you a shortcut path or a alternate path where you can get access to properties and values of documents.
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const mongoose = require('mongoose');
main().catch(err => console.log(err));
async function main() {
await mongoose.connect('mongodb://127.0.0.1:27017/StudentData');
const studentSchema = new mongoose.Schema({
studentName : {
type: String,
alias: 'name',
},
studentEmail : {
type : String,
alias : 'email',
},
studentAddress : {
state : { type : String, alias : "st"},
district : { type : String, alias : "dist"},
city : { type : String, alias : "ct"},
},
scienceMarks : {
theoryPaper : {
physics : { type : Number, alias : "phTheo"},
chemistry : { type : Number, alias : "chTheo"},
mathematics : { type : Number, alias : "mtTheo"},
},
practicalPaper : {
physics : { type : Number, alias : "phPrt"},
chemistry : { type : Number, alias : "chPrt"},
mathematics : { type : Number, alias : "mtPrt"},
}
}
},
{
methods: {
getStudentBioData() {
const bioData = "name is : "+this.name+", email is : "+this.email;
return bioData;
},
getStudentLocationData() {
const locationData = "Student is currently living in state : "+this.st+", at district is : "+this.dist+
", at city is : "+this.ct;
return locationData;
},
getStudentScienceMarks(){
let physicsTotal, chemistryTotal , mathematicsTotal;
physicsTotal = this.phTheo + this.phPrt;
chemistryTotal = this.chTheo + this.chPrt;
mathematicsTotal = this.mtTheo + this.mtPrt;
this.getHelloStudents(this.name, physicsTotal + chemistryTotal + mathematicsTotal);
return "Marks in physics = "+physicsTotal+", chemistry = "+chemistryTotal+", mathematics = "+mathematicsTotal;
},
getHelloStudents(stuName, totalMarks){
let grade, average;
average = (totalMarks / 3).toFixed(2);
if(average >= 90){
grade = "Excellent";
}
else if(average >= 70 && average < 90){
grade = "Very Good";
}
else if(average >= 50 && average < 70){
grade = "Good";
}
else if(average >= 30 && average < 50){
grade = "Pass";
}
else{
grade = "Fail";
}
console.log(stuName+" , has got total marks of = "+totalMarks+", average = "+average
+ ",\n with a grade of : "+grade);
}
}
}
);
const Student = mongoose.model('Student', studentSchema);
await Student.insertMany([
{
name : "Mayuk Mukherjee",
email : "Mayuk@gmail.com",
st : "California",
dist : "Ohio",
ct : "Colorado",
phTheo : 79,
chTheo : 68,
mtTheo : 77,
phPrt : 18,
chPrt : 16,
mtPrt : 19,
},
{
name : "Suryendu Sarkar",
email : "Suryendu@gmail.com",
st : "Alabama",
dist : "Denver",
ct : "California",
phTheo : 49,
chTheo : 58,
mtTheo : 58,
phPrt : 12,
chPrt : 18,
mtPrt : 12
},
{
name : "Aninda Mukherjee",
email : "Aninda@gmail.com",
st : "Alaska",
dist : "Texas",
ct : "Huston",
phTheo : 54,
chTheo : 59,
mtTheo : 42,
phPrt : 15,
chPrt : 20,
mtPrt : 14,
},
{
name : "Sanlap Gadai",
email : "Sanlap@gmail.com",
st : "MAssachuttes",
dist : "Ohio",
ct : "Atlanta",
phTheo : 66,
chTheo : 61,
mtTheo : 59,
phPrt : 18,
chPrt : 12,
mtPrt : 14,
},
]);
const allStudent = await Student.find({});
console.log(allStudent);
console.log("total students number = "+allStudent.length+"\n");
for(var i = 0; i < allStudent.length; i++){
console.log(allStudent[i].getStudentBioData());
console.log(allStudent[i].getStudentLocationData());
console.log(allStudent[i].getStudentScienceMarks());
console.log("\n");
}
}
Go through this code very carefully .
Check this output given below :
PS C:\Users\USER\Downloads\mongoExpress\Alias_Schema> node src/alias_2.js
[
{
studentAddress: { state: 'California', district: 'Ohio', city: 'Colorado' },
scienceMarks: { theoryPaper: [Object], practicalPaper: [Object] },
_id: new ObjectId('65c50e0667aa21025fa5f6dc'),
studentName: 'Mayuk Mukherjee',
studentEmail: 'Mayuk@gmail.com',
__v: 0
},
{
studentAddress: { state: 'Alabama', district: 'Denver', city: 'California' },
scienceMarks: { theoryPaper: [Object], practicalPaper: [Object] },
_id: new ObjectId('65c50e0667aa21025fa5f6dd'),
studentName: 'Suryendu Sarkar',
studentEmail: 'Suryendu@gmail.com',
__v: 0
},
{
studentAddress: { state: 'Alaska', district: 'Texas', city: 'Huston' },
scienceMarks: { theoryPaper: [Object], practicalPaper: [Object] },
_id: new ObjectId('65c50e0667aa21025fa5f6de'),
studentName: 'Aninda Mukherjee',
studentEmail: 'Aninda@gmail.com',
__v: 0
},
{
studentAddress: { state: 'MAssachuttes', district: 'Ohio', city: 'Atlanta' },
scienceMarks: { theoryPaper: [Object], practicalPaper: [Object] },
_id: new ObjectId('65c50e0667aa21025fa5f6df'),
studentName: 'Sanlap Gadai',
studentEmail: 'Sanlap@gmail.com',
__v: 0
}
]
total students number = 4
name is : Mayuk Mukherjee, email is : Mayuk@gmail.com
Student is currently living in state : California, at district is : Ohio, at city is : Colorado
Mayuk Mukherjee , has got total marks of = 277, average = 92.33,
with a grade of : Excellent
Marks in physics = 97, chemistry = 84, mathematics = 96
name is : Suryendu Sarkar, email is : Suryendu@gmail.com
Student is currently living in state : Alabama, at district is : Denver, at city is : California
Suryendu Sarkar , has got total marks of = 207, average = 69.00,
with a grade of : Good
Marks in physics = 61, chemistry = 76, mathematics = 70
name is : Aninda Mukherjee, email is : Aninda@gmail.com
Student is currently living in state : Alaska, at district is : Texas, at city is : Huston
Aninda Mukherjee , has got total marks of = 204, average = 68.00,
with a grade of : Good
Marks in physics = 69, chemistry = 79, mathematics = 56
name is : Sanlap Gadai, email is : Sanlap@gmail.com
Student is currently living in state : MAssachuttes, at district is : Ohio, at city is : Atlanta
Sanlap Gadai , has got total marks of = 230, average = 76.67,
with a grade of : Very Good
Marks in physics = 84, chemistry = 73, mathematics = 73
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