Query

Learn Mongoose queries and filtering.

What is a Query?

A Query in Mongoose is a database search operation. Model.find(condition) returns a Query object; it runs asynchronously and you await it.

Core query methods: find() (all matches), findOne() (first match), findById(id) (by ID). The filter is an object: { age: { $gt: 18 } } finds documents where age is greater than 18. Queries are chainable: User.find(filter).sort({ name: 1 }).limit(10).

find, findById, findOne

There are three core search methods. find(filter) returns all matching documents as an array. findOne(filter) returns the first matching document. findById(id) finds a single document by its unique ID.

All are asynchronous; you use them with await. An empty filter {} returns all documents. If no document matches, find returns an empty array [], while findOne and findById return null.

Exercise Log the type of find

Import mongoose. Create a model with mongoose.model("User", { name: String }). Log typeof User.find.

Show example solution

const mongoose = require("mongoose");
const User = mongoose.model("User", { name: String });
console.log(typeof User.find);

Test yourself

What does User.find() return?
- Bir dize
- A number
- Bir Buffer
- Bir Query nesnesi
Show answer

Bir Query nesnesi — User.find() returns a Query object.
Match each piece to its role

Model.find()

Finds all docs
Model.findById()

Finds by ID
Model.findOne()

Finds one doc
Query

Query object

Complete the method name

const results = await User.____({})

Show answer

const results = await User.find({})

Next lesson: Aggregate

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