MongoDB¶

mongosh // enter
exit // exit

show dbs
use appdb
show collections
db.dropDatabase()

db.users.insertOne({
    name: "Ahmed"
})
db.users.insertMany([
  {
    name: "Ahmed"
  },
    {
    name: "Thahir"
  }
])

db.users.findOne()
db.users.find() // equiv to select *

.sort({
    name:1, // -1
    age: 1
})
.skip(5)
.limit(10)

db.users.countDocuments({
  age: 10
})

db.users.updateOne(
  {
    age: 26
    },
  {
    $set: {age: 27}
  }
)
db.users.updateMany(
  {
    age: 26
    },
  {
    $set: {age: 27}
  }
)

$set
$inc
$rename: {name: "Ahmed"}
$unset: {name: ""} // removes key; doesn't set to null
$push: {hobbies: "Swimming"} // adding to array key
$pull: {hobbies: "Swimming"} // remove from array key

db.users.replaceOne(
  {
    age: 26
    },
  {
    name: "Thahir"
  }
)
db.users.replace(
  {
    age: 26
    },
  {
    name: "Thahir"
  }
)

db.users.deleteOne(
  {
    name: "Thahir"
  }
)
db.users.deleteMany(
  {
    name: "Thahir"
  }
)

// filter Thahir and return only name and age
db.users.find(
  {
    name: "Thahir"
  },
  {
    name: 1,
    age:1,
    _id: 0
  }
)

db.users.find(
  {
    first_name: {$eq: "Ahmed"},
    age: {$gte: 50},
  },
  {
    name: 1,
    age:1,
    _id: 0
  }
)

{$eq: "Thahir"}
{$ne: "Thahir"}
{$gte: 10}
{$in: [
  "Ahmed",
  "Thahir",
  5
]}
{$nin: [
  "Ahmed",
  "Thahir",
  5
]}
{$exists: true} // only checks if key exists; hence includes documents with null
{$exists: false}

// not
{
    not: [
    {filter_1: "enset"}
  ]
}

// and
{
    filter_1: "enset",
  filter_2: "enset"
}

{
    $and: [
    {filter_1: "enset"},
      {filter_2: "enset"}
  ]
}

// or
{
    $or: [
    {filter_1: "enset"},
      {filter_2: "enset"}
  ]
}

db.users.find({
  $expr: {
    $gt: ["$debt", "$balance"]
  }
})

db.users.find({
  "address.street": "Testing"
})