Appendix D. MongoDB and Mongoose cheatsheet

When you develop your own projects, searching on the internet for React documentation and APIs or going back to this book’s chapters to find a single method isn’t efficient. If you’d like to save time and avoid the distractions lurking everywhere on the Net, use this MongoDB cheatsheet as a quick reference.

MongoDB

• $ mongod—Starts the MongoDB server (localhost:27017)
• $ mongo (connects to the local server by default)—Opens the MongoDB console

MongoDB console

• > show dbs—Shows databases on the server
• > use DB_NAME—Selects the database DB_NAME
• > show collections—Shows collections in the selected database
• > db.COLLECTION_NAME.find()—Performs a find query on the collection named COLLECTION_NAME to find any items
• > db.COLLECTION_NAME.find({"_id"—ObjectId("549d9a3081d0f07866fdaac6") })—Performs a find query on the collection named COLLECTION_NAME to find the item with ID 549d9a3081d0f07866fdaac6
• > db.COLLECTION_NAME.find({"email": /gmail/})—Performs a find query on the collection named COLLECTION_NAME to find items with an email property matching /gmail
• > db.COLLECTION_NAME.update(QUERY_OBJECT, SET_OBJECT)—Performs an update query on the collection named COLLECTION_NAME to update items that match QUERY_OBJECT with SET_OBJECT
• > db.COLLECTION_NAME.remove(QUERY_OBJECT)—Performs a remove query for items matching QUERY_OBJECT criteria on the COLLECTION_NAME collection
• > db.COLLECTION_NAME.insert(OBJECT)—Adds OBJECT to the collection named COLLECTION_NAME

Installing Mongoose

• $ sudo npm install mongoose—Installs the latest version of Mongoose locally
• $ sudo npm install [email protected] --save—Installs Mongoose v3.8.20 locally, and saves it to package.json

Mongoose basic usage

var mongoose = require('mongoose')
var dbUri = 'mongodb://localhost:27017/api'
var dbConnection = mongoose.createConnection(dbUri)
var Schema = mongoose.Schema
var postSchema = new Schema ({
  title: String,
  text: String
})
var Post = dbConnection.model('Post', postSchema, 'posts')
Post.find({},function(error, posts){
  console.log(posts)
  process.exit(1)
})

Mongoose schema

• String
• Boolean
• Number
• Date
• Array
• Buffer
• Schema.Types.Mixed
• Schema.Types.ObjectId

Create, read, update, delete (CRUD) Mongoose example

// Create
var post = new Post({title: 'a', text: 'b')
post.save(function(error, document){
  ...
})
// Read
Post.findOne(criteria, function(error, post) {
  ...
})
// Update
Post.findOne(criteria, function(error, post) {
  post.set()
  post.save(function(error, document){
    ...
  })
})
// Delete
Post.findOne(criteria, function(error, post) {
  post.remove(function(error){
    ...
  })
})

Mongoose model methods

• find(criteria, [fields], [options], [callback]), where callback has error and documents arguments—Finds a document
• count(criteria, [callback])), where callback has error and count arguments—Returns a count of documents with matching criteria
• findById(id, [fields], [options], [callback]), where callback has error and document arguments—Returns a single document by ID
• findByIdAndUpdate(id, [update], [options], [callback])—Executes MongoDB’s findAndModify() to update a document by ID
• findByIdAndRemove(id, [options], [callback])—Executes MongoDB’s findAndModify() to remove a document by ID
• findOne(criteria, [fields], [options], [callback]), where callback has error and document arguments—Returns a single document
• findOneAndUpdate([criteria], [update], [options], [callback])—Executes MongoDB’s findAndModify() to update document(s)
• findOneAndRemove(id, [update], [options], [callback])—Executes MongoDB’s findAndModify() to remove a document
• update(criteria, update, [options], [callback]), where callback has error and count arguments—Updates documents
• create(doc(s), [callback]), where callback has error and doc(s) arguments—Creates a document object, and saves it to the database
• remove(criteria, [callback]), where callback has an error argument—Removes documents

Mongoose document methods

• save([callback]), where callback has error, doc, and count arguments—Saves the document
• set(path, val, [type], [options])—Sets a value on the document’s property
• get(path, [type])—Gets the value of a property
• isModified([path])—Checks whether a property has been modified
• populate([path], [callback])—Populates a reference
• toJSON(options)—Gets JSON from the document
• validate(callback)—Validates the document