How to specify that at least one field is required out of three in total? - mongodb

Question

In my MongoDB model, there are 3 fields in total. Any document added to this collection must contain at least 1 of those 3 fields.
How can this be specified in the validation staged?

Answer 1

You can enum validation constraint which collection creation as below:
db.createCollection("jobs", {
validator: {
$jsonSchema: {
bsonType: "object",
required: [ "status" ],
properties: {
status: {
enum: [ "Done", "Failed", "Initial" ],
description: "can only be one of the enum values and is required"
},
}
}
}
})
From the docs
Mongoose has several inbuilt validators. Strings have enum as one of the validators. So enum creates a validator and checks if the value is given in an array. E.g:
var userSchema = new mongooseSchema({
status: {
type: String,
enum : ['Done','Failed', 'Initial'],
default: 'Initial'
},
})
You can use custom validator to check if we have one of 3 keys in the object
const testSchema = mongoose.Schema({
field1: {
type: String,
validate: {
validator: function(v) {
if (this.field2 == undefined && this.field3 == undefined) {
return true;
}
return false;
},
},
},
field2: {
type: String,
validate: {
validator: function(v) {
if (this.field1 == undefined && this.field3 == undefined) {
return true;
}
return false;
},
},
},
field3: {
type: String,
validate: {
validator: function(v) {
if (this.field2 == undefined && this.field1 == undefined) {
return true;
}
return false;
},
},
},
});