I am using mongoose as an ODM and trying to model an animal/pet. In the model I have 2 fields, parent and shelter. I want to make sure that pet belongs to a person or a shelter but not both. What constraints would allow me to do this.
My model in JS:-
const petSchema = mongoose.Schema({
name: {
type: String,
required: [true, "Pet must have a name."],
trim: true
},
species: {
type: String,
required: [true, "Pet must have a species."]
},
parent: {
type: mongoose.Schema.Types.ObjectId,
ref: 'User'
},
shelter: {
type: mongoose.Schema.Types.ObjectId,
ref: 'Shelter'
}
}
I am new to databases and their jargons, correct me if any error in question. Thank you.
You can use the required function to determine this as follows:
const petSchema = mongoose.Schema({
name: {
type: String,
required: [true, "Pet must have a name."],
trim: true
},
species: {
type: String,
required: [true, "Pet must have a species."]
},
parent: {
type: mongoose.Schema.Types.ObjectId,
ref: 'User',
required: function() {
return !this.shelter;
}
},
shelter: {
type: mongoose.Schema.Types.ObjectId,
ref: 'Shelter',
required: function() {
return !this.parent;
}
}
}
I ended up using pre validate middleware in mongoose:-
petSchema.pre('validate', function (next) {
if((this.parent && this.shelter) || (!this.parent && !this.shelter))
return next(new Error("At least and Only one field(parent, shelter) should be populated"))
next()
})