MongoDB Cheat Sheet

MongoDB_Cheat_Sheet.md

Local Mongo

• Run mongod:

mongod --dbpath D:\NICK\Mongo\data --port 27017 --storageEngine wiredTiger

• Create admin, site root users

use admin
db.createUser( {
  user: "adminuser",
 pwd: "user",
 roles: [ { role: "userAdminAnyDatabase", db: "admin" } ]
});
db.createUser( {
 user: "siterootadmin",
 pwd: "siteroot",
 roles: [ { role: "root", db: "admin" } ]
});

• Create new db and add user

use mydb
db.createUser( {
 user: "mydbadmin", 
 pwd: "mydb",
 roles:[ { role: "dbOwner", db: "inv" } ]
});

• Create collection:

db.createCollection("mycol")

• Insert Doc via CLI

db.mycol.insert({"City":"Houma","State":"LA","ZipCode":"70360"})

• Insert Doc via JSON file (new cmd window)

mongoimport --db inv --collection plants --file example1.json

• Insert Doc via a JSON Array file (shorthand params)

mongoimport --jsonArray -d test -c docs --file example2.json

• Set a variable - set to first file in current directory

myvar = "myvar"

• Run a js script

load("myscript.js")

• Print out json from JS script (any method that returns a cursor)

cursor = db.mycollection.find({})
while (cursor.hasNext()) {
  printjson(cursor.next());
}

• List all files in current dir

ls()

Node JS

• Using batchSize in bulk operations. Found here

cursor = useDb.collection('millions').find().limit(limit).batchSize(arraySize);

for (let doc = await cursor.next(); doc != null; doc = await cursor.next()) {
    counter++;
}

Quick Links

Comparing data

• Compare collections in Studio3T
• .NET Tool for comparing
• Get a MD5 hash for db or collection
• Compare a mongo diff on two collections

Aggreate Pipeline Help

• $unwind - Unwind arrays
• $expr - Perform expression
• $lookup - Merge objects
• Pipeline Optimizations
• Add $comment to your pipelines
• Conditionally Exclude Fields
• Feild Level Redaction based on user access
• $cond - if else statement
• $map - apply to each element in array
• $eq- Equals operation

Dump and Restore

• Tools for MongoDB Backup
• mongodump
• mongorestore

Performance Optimization

• understand-mongodb-cache-system
• how to optimize performance mongodb
• Simple speedup tips

Third Party Solutions

• Percona - MongoDB Monitoring
• Studio 3T - MongoDB GUI
• mLab - MongoDB Hosting

Lookup

• mongodb-query-multiple-collections-at-once