MongoDB crud R

Document Query

Command	Operation
db.mycoll.find(key:value)	Data for query condition
db.mycoll.find(...).count()	Querying and Counting
db.mycoll.find(...).limit(n)	Limit the number of query bars
db.mycoll.find(...).skip(n)	Skip a query
db.mycoll.find(...).sort(...)	Query and sort
db.mycoll.find(...).pretty()	Querying and optimizing output results

Read View all

25 > db.set2test.find(){ "_id" : ObjectId("5a7943273fdd5fec85460638"), "x" : 3 }{ "_id" : ObjectId("5a7943273fdd5fec85460639"), "x" : 4 }{ "_id" : ObjectId("5a7943273fdd5fec8546063a"), "x" : 5 }.......{ "_id" : ObjectId("5a7943273fdd5fec8546064b"), "x" : 22 }Type "it" for more26 > it{ "_id" : ObjectId("5a7943273fdd5fec8546064c"), "x" : 23 }{ "_id" : ObjectId("5a7943273fdd5fec8546064d"), "x" : 24 }{ "_id" : ObjectId("5a7943273fdd5fec8546064e"), "x" : 25 }

Enter it to see more data

Specify fields

44 > db.unicorns.find({},{_id: 0, name: 1, gender: 1, weight: 1}){ "name" : "Aurora", "gender" : "f", "weight" : 450 }{ "name" : "Horny", "weight" : 600, "gender" : "m" }{ "name" : "Aurora", "weight" : 450, "gender" : "f" }{ "name" : "Unicrom", "weight" : 984, "gender" : "m" }{ "name" : "Roooooodles", "weight" : 575, "gender" : "m" }{ "name" : "Solnara", "weight" : 550, "gender" : "f" }{ "name" : "Ayna", "weight" : 733, "gender" : "f" }{ "name" : "Kenny", "weight" : 690, "gender" : "m" }{ "name" : "Raleigh", "weight" : 421, "gender" : "m" }{ "name" : "Leia", "weight" : 601, "gender" : "f" }{ "name" : "Pilot", "weight" : 650, "gender" : "m" }{ "name" : "Nimue", "weight" : 540, "gender" : "f" }{ "name" : "Dunx", "weight" : 704, "gender" : "m" }

Conditional query

45 > db.unicorns.find({weight: {$gt: 700}},{_id: 0, name: 1, gender: 1, weight: 1}){ "name" : "Unicrom", "weight" : 984, "gender" : "m" }{ "name" : "Ayna", "weight" : 733, "gender" : "f" }{ "name" : "Dunx", "weight" : 704, "gender" : "m" }

Size

operator	meaning	symbols
$gt	Greater than	>
$gte	GT equal	>=
$lt	Less than	<
$lte	Lt equal	<=
$ne	Not equal	!=
$eq	Equal	=

41 > db.unicorns.find({weight: {$gt: 700}}).count()3

Logic

operator	meaning	symbols
$or	Or	||
$and	and	&&

48 > db.unicorns.find({    $and:     [{weight: {$gt: 700}},{gender: 'f'}]    }, {    _id: 0,     name: 1,     gender: 1, weight: 1    

Equivalent to

49 > db.unicorns.find(    {        weight: {$gt: 700},gender: 'f'        },     {        _id: 0, name: 1, gender: 1, weight: 1        }){ "name" : "Ayna", "weight" : 733, "gender" : "f" }

Fuzzy

• Regular

54 > db.unicorns.find({name: {$regex: /^[A-D]/}}, {_id: 0, name: 1}){ "name" : "Aurora" }{ "name" : "Aurora" }{ "name" : "Ayna" }{ "name" : "Dunx" }

• Whether the key value exists or not

61 > db.unicorns.find({ loves: { $exists: false } }, {_id: 0}){ "name" : "Aurora", "gender" : "f", "weight" : 450 }

• Range

64 > db.unicorns.find({ name: { $in: ["Ayna", "Aurora"] } }, {_id: 0, name: 1, gender: 1, weight: 1}){ "name" : "Aurora", "gender" : "f", "weight" : 450 }{ "name" : "Aurora", "weight" : 450, "gender" : "f" }{ "name" : "Ayna", "weight" : 733, "gender" : "f" }

Similarly, there are$nin

More query operators see here

Output optimization

28 > db.unicorns.find({gender:'f'}).pretty(){    "_id" : ObjectId("5a793d993fdd5fec8546062b"),    "name" : "Aurora",    "gender" : "f",    "weight" : 450}{    "_id" : ObjectId("5a79408c3fdd5fec8546062d"),    "name" : "Aurora",    "dob" : ISODate("1991-01-24T05:00:00Z"),    "loves" : [        "carrot",        "grape"    ],    "weight" : 450,    "gender" : "f",    "vampires" : 43}......

Sort Ascending

30 > db.unicorns.find().sort({weight:1}){ ... "weight" : 421,... }{ ... "weight" : 450 }{ ... "weight" : 450, "gender" : "f", "vampires" : 43 }{ ... "weight" : 540, "gender" : "f" }{ ... "weight" : 550, "gender" : "f", "vampires" : 80 }{ ... "weight" : 575, "gender" : "m", "vampires" : 99 }{ ... "weight" : 600, "gender" : "m", "vampires" : 63 }{ ... "weight" : 601, "gender" : "f", "vampires" : 33 }{ ... "weight" : 650, "gender" : "m", "vampires" : 54 }{ ... "weight" : 690, "gender" : "m", "vampires" : 39 }{ ... "weight" : 704, "gender" : "m", "vampires" : 165 }{ ... "weight" : 733, "gender" : "f", "vampires" : 40 }{ ... "weight" : 984, "gender" : "m", "vampires" : 182 }

Descending

31 > db.unicorns.find().sort({weight:-1}){ ... "weight" : 984, "gender" : "m", "vampires" : 182 }{ ... "weight" : 733, "gender" : "f", "vampires" : 40 }{ ... "weight" : 704, "gender" : "m", "vampires" : 165 }{ ... "weight" : 690, "gender" : "m", "vampires" : 39 }{ ... "weight" : 650, "gender" : "m", "vampires" : 54 }{ ... "weight" : 601, "gender" : "f", "vampires" : 33 }{ ... "weight" : 600, "gender" : "m", "vampires" : 63 }{ ... "weight" : 575, "gender" : "m", "vampires" : 99 }{ ... "weight" : 550, "gender" : "f", "vampires" : 80 }{ ... "weight" : 540, "gender" : "f" }{ ... "weight" : 450 }{ ... "weight" : 450, "gender" : "f", "vampires" : 43 }{ ... "weight" : 421, "gender" : "m", "vampires" : 2 }

Paging Query

37 > db.unicorns.find().sort({weight:-1}).limit(2).skip(10).pretty(){    "_id" : ObjectId("5a793d993fdd5fec8546062b"),    "name" : "Aurora",    "gender" : "f",    "weight" : 450}{    "_id" : ObjectId("5a79408c3fdd5fec8546062d"),    "name" : "Aurora",    "dob" : ISODate("1991-01-24T05:00:00Z"),    "loves" : [        "carrot",        "grape"    ],    "weight" : 450,    "gender" : "f",    "vampires" : 43}

Count

39 > db.unicorns.find({gender: 'f'}).count()6

Go heavy

67 > db.unicorns.distinct("gender")[ "f", "m" ]

MongoDB crud R