Mongo Cheatsheet

MongoCheatSheet.md

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Mongo Database Cheatsheet

Content:

1. Setup Mongo
2. Tools
3. Most used commands
4. Mongoose

• 4.1 Setting up a Model
• 4.2 create new documents in database
• 4.3 find queries
• 4.4 update queries
• 4.5 others

5. export / import databas

1. Setup MongoDB

See more

Installation

Options:

• Mongo Atlas free tier or paid database - registrate and create
• locally installed MongoDB on computer - install
• local MongoDB in docker container - pull from dockerhub (should have Docker Desktop)

Here I use the last option:

  docker pull mongo
  docker run -p 27018:27017 --name myAppDatabase mongo

2. Tools

• Mongo Atlas
  Online free MongoDB. It provides also an online interface to browse documents
• Mongo Compass
  GUI which can connect local and remote Mongo databases. Makes your life easier if you use locally installed or dockerized Mongo

3. Most used commands

4. Mongoose

note: I shortened the queries for a better focus, but of course you can always receive return values. You should also use then or await, because a mongo query always returns a thenable object (or a Promise if you use .exec() ).

  const allTheFruits = await Fruit.find();

Setting up a Model

create new documents in database

• Create multiple documents

  Fruit.create(fruitArray);

• Function to create one document:

async function newFruit({ name, color, ...optionalFields }) {
  Fruit.create({
    fruitName: name,
    color: color,
    ...optionalFields,
  });
}

await newFruit('orange', 'orange', ')

find queries

• Find one item by id: Fruit.findById(bananaId)

• Find all items in a collection: Fruit.find()

• Example for find query with filtering:

  Customer.find({
    $and: [
      {
        $or: [
          {
            Country: "Germany",
          },
          {
            Country: "France",
          },
        ],
      },
      {
        VIP: true,
      },
    ],
  });

• Filtering options:

  • $ne not equal (!=)
  • $eq equal (=)
  • $gt greater than (>)
  • $gte greater or equal than (>=)
  • $in in (in)
  • $lt less than (<)
  • $lte less or equal than (<=)
  • $nin not in (not in)

update queries

• Add an item to a document's field which is an array

  const updatedMan  = await Man.updateOne(
      { _id: manId },
      { $push: { pastGirlfriends: SusansId } },
      done
  );

others

  Fruit.count();
  Fruit.deleteMany();

.lean()

export / import database

mongoexport --uri [mongo db connection url]/[database name] --collection [collection name] --out [filename].json

mongoimport --uri [mongo db connection url]/[database name] --collection  [collection name]  --drop --file [filename path].json