Q1. How do you create a document with Mongoose?
Two ways: using new and save, or using create():
const user = new User({ name: 'John', age: 30 });
await user.save();
// or
const user = await User.create({ name: 'John', age: 30 });
Q2. How do you query documents with Mongoose?
Mongoose provides static and instance methods:
const users = await User.find({ age: { $gt: 25 } });
const user = await User.findOne({ email: 'john@example.com' });
const userById = await User.findById('507f1f77bcf86cd799439011');
Q3. How do you update documents?
Using updateOne, updateMany, or findAndUpdate:
await User.updateOne({ name: 'John' }, { age: 31 });
const user = await User.findByIdAndUpdate(id, { age: 31 }, { new: true });
Q4. How do you delete documents?
Use deleteOne, deleteMany, or findAndDelete:
await User.deleteOne({ name: 'John' });
const user = await User.findByIdAndDelete(id);
Q5. How do you add validation in Mongoose?
Validation is defined in the schema:
const userSchema = new mongoose.Schema({
name: { type: String, required: [true, 'Name is required'] },
age: { type: Number, min: 18, max: 100 },
email: {
type: String,
validate: {
validator: v => /S+@S+.S+/.test(v),
message: props => `${props.value} is not a valid email!`
}
}
});