How to define a single reference schema using mongoose - node.js

Question

I am new in node.js and mongodb and as in the below code i define a reference in table employee of department but here when I insert or get data from employee table i always get in array format but i want to define reference as single column not multiple.
var employee = new mongoose.Schema({
name: String,
dept: [department]
});
var department = new mongoose.Schema({
dept_name : String,
dept_code : String
})
I want data in response from employee table in format `{"name":"CS",dept:{"id":_id_of_dept}}
Please guide me the correct way to achieve my objective.

Answer 1

You can only nest using references or arrays, so in this example, you can either create a department record and reference that in the employee document, or have an array of departments for the employee (which I understand is not what you want to do).
To reference the department document from your employee you would use something like:
var department = new mongoose.Schema({
dept_name : String,
dept_code : String
});
mongoose.model('Department', department);
var employee = new mongoose.Schema({
name: String,
dept: { type: Schema.Types.ObjectId, ref: 'Department' }
});
However, then you'll need to populate when querying your employee to gather the department data.
But at a high level, looking at what you're trying to accomplish, I'd suggest just directly storing the department within the employee document. Relational databases may often end up with patterns like you've described above, but in document based databases, there's really not a good reason to separate out the department from the employee. Doing something like what I've put below will help you in the future for queries and general access of the data:
var employee = new mongoose.Schema({
name: String,
dept: {
dept_name : String,
dept_code : String
}
});
This answer might be helpful in understanding what I mean.