Mongo CRUD data operator summary, javascrud

Mongo CRUD data operator summary, javascrud

Comparison

Name	Description
$ Eq	Equal
$ Gt	Greater
$ Gte	Greater than or equal
$ Lt	Less
$ Lte	Less than or equal
$ Ne	Not equal
$ In	In the condition
$ Nin	Not in the condition

Logic

Name	Description
$ Or	Or
$ And	And
$ Not	Non
$ Nor	Neither nor, nor: [{name: 'bucketall', age: 12}]. The name is not 'bucketall', and the age is not 12.

Element

Name	Description
$ Exists	Whether the field exists
$ Type	Field Type

Array

Name	Description
$ All	Obtain all data that meets the conditions
$ ElemMatch	Obtain all the data that meets the conditions.
$ Size	If the returned value is an array, define the number of returned array elements.

Remarks

Name	Description
$ Comment	Add a description or remarks to the command.

"

$ Where

db.myCollection.find( { $where: "this.credits == this.debits" } );db.myCollection.find( { $where: "obj.credits == obj.debits" } );db.myCollection.find( { $where: function() { return (this.credits == this.debits) } } );db.myCollection.find( { $where: function() { return obj.credits == obj.debits; } } );

Where accepts parameters in two forms of string functions. Some functions are also provided.

assert()BinData()DBPointer()DBRef()doassert()emit()gc()HexData()hex_md5()isNumber()isObject()ISODate()isString()Map()MD5()NumberInt()NumberLong()ObjectId()print()printjson()printjsononeline()sleep()Timestamp()tojson()tojsononeline()tojsonObject()UUID()version()

Note:

Because the execution plan generated by mongo after $ where is used cannot use indexes well, we do not recommend that you use $ where

$ All

Select all data that meets the conditions ).

    { <field>: { $all: [ <value1> , <value2> ... ] } }

$ All has the same functions as $ and, for example, $ and:

    { $and: [ { tags: "ssl" }, { tags: "security" } ] }

$ And

    { $and: [ { tags: "ssl" }, { tags: "security" } ] }

$ BatchSize

db.inventory.find().batchSize(10)

Control the number of data records returned. Note that the batchSize () setting does not take effect in mongo shell. At the same time, distinct () does not take effect.

$ Box

db.places.find( {   loc: { $geoWithin: { $box:  [ [ 0, 0 ], [ 100, 100 ] ] } }} )

Define a "box" with two points to determine the position of a "box" (we understand the box as a rectangle of a two-dimensional plane ), the above sentence means to find the points in the box, [], [], [], [], and []. All these values will be returned.

$ Center

    db.places.find(   { loc: { $geoWithin: { $center: [ [-74, 40.74], 10 ] } } })

Returns all points in the circular area (Center Coordinate is (-74, 40.74), and circle radius is 10)

$ Comment

    db.collection.find( { $query: { <query> }, $comment: <comment> } )

It can be understood that each execution adds a note, which will be recorded in the profile, which helps to troubleshoot problems in the future.

$ Count

    db.collection.find( { a: 5, b: 5 } ).count()

Count

$ Distinct

    db.collection.distinct(field, query)

Deduplication

$ ElemMatch

    { <field>: { $elemMatch: { <query1>, <query2>, ... } } }    { _id: 1, results: [ 82, 85, 88 ] }    { _id: 2, results: [ 75, 88, 89 ] }    db.scores.find(       { results: { $elemMatch: { $gte: 80, $lt: 85 } } }    )

Satisfying the first interval

$ Exists

    { field: { $exists: <boolean> } }    db.records.find( { a: { $exists: true } } )    result:        { a: 5, b: 5, c: null }        { a: 3, b: null, c: 8 }        { a: null, b: 3, c: 9 }        { a: 1, b: 2, c: 3 }        { a: 2, c: 5 }        { a: 3, b: 2 }        { a: 4 }    db.records.find( { b: { $exists: false } } )    result:        { a: 2, c: 5 }        { a: 4 }        { c: 6 }

$ Find

    query.find({ name: 'Los Pollos Hermanos' }).find(callback)

Search for all qualified data

$ FindOne

    query.findOne({ name: 'Los Pollos Hermanos' }).find(callback)

Returns a data that meets the condition.

$ FindAndModify

    {          findAndModify: <collection-name>,          query: <document>,          sort: <document>,          remove: <boolean>,          update: <document>,          new: <boolean>,          fields: <document>,          upsert: <boolean>    }

Field	Description
Query	A common request statement may obtain multiple data records, but findAndModify only processes the first data entry.
Sort	Because findAndModify can only process one piece of data, we usually sort the data obtained by the query.
Remove	If true, the first data record after the query is removed. The default value is false.
Update	The first entry after the query is updated
New	When set to true, the modified data instead of the original data is returned. The default value is false.
Fields	Set Group
Upsert	When the value is true, the updated value is updated if it exists, and inserted if it does not exist. The default value is false.

db.people.findAndModify( {   findAndModify: "people",   query: { name: "Gus", state: "active", rating: 100 },   sort: { rating: 1 },   update: { $inc: { score: 1 } },   upsert: true,   new : true} );