Azure Cosmos DB's API for MongoDB (3.6 version): supported features and syntax
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Azure Cosmos DB API for MongoDB
Azure Cosmos DB is Microsoft's globally distributed multi-model database service. You can communicate with the Azure Cosmos DB's API for MongoDB using any of the open-source MongoDB client drivers. The Azure Cosmos DB's API for MongoDB enables the use of existing client drivers by adhering to the MongoDB wire protocol.
By using the Azure Cosmos DB's API for MongoDB, you can enjoy the benefits of the MongoDB you're used to, with all of the enterprise capabilities that Cosmos DB provides: global distribution, automatic sharding, availability and latency guarantees, encryption at rest, backups, and much more.
Note
Version 3.6 of the Cosmos DB API for MongoDB has no current plans for end-of-life (EOL). The minimum notice for a future EOL is three years.
Protocol Support
The Azure Cosmos DB's API for MongoDB is compatible with MongoDB server version 3.6 by default for new accounts. The supported operators and any limitations or exceptions are listed below. Any client driver that understands these protocols should be able to connect to Azure Cosmos DB's API for MongoDB. Note that when using Azure Cosmos DB's API for MongoDB accounts, the 3.6 version of account has the endpoint in the format *.mongo.cosmos.azure.com whereas the 3.2 version of account has the endpoint in the format *.documents.azure.com.
Query language support
Azure Cosmos DB's API for MongoDB provides comprehensive support for MongoDB query language constructs. The following sections show the detailed list of server operations, operators, stages, commands, and options currently supported by Azure Cosmos DB.
Note
This article only lists the supported server commands and excludes client-side wrapper functions. Client-side wrapper functions such as deleteMany() and updateMany() internally utilize the delete() and update() server commands. Functions utilizing supported server commands are compatible with Azure Cosmos DB's API for MongoDB.
Database commands
Azure Cosmos DB's API for MongoDB supports the following database commands:
$lookup does not yet support the uncorrelated subqueries feature introduced in server version 3.6. You will receive an error with a message containing let is not supported if you attempt to use the $lookup operator with let and pipeline fields.
Boolean expressions
Command
Supported
$and
Yes
$not
Yes
$or
Yes
Set expressions
Command
Supported
$setEquals
Yes
$setIntersection
Yes
$setUnion
Yes
$setDifference
Yes
$setIsSubset
Yes
$anyElementTrue
Yes
$allElementsTrue
Yes
Comparison expressions
Note
The API for MongoDB does not support comparison expressions with an array literal in the query.
Command
Supported
$cmp
Yes
$eq
Yes
$gt
Yes
$gte
Yes
$lt
Yes
$lte
Yes
$ne
Yes
$in
Yes
$nin
Yes
Arithmetic expressions
Command
Supported
$abs
Yes
$add
Yes
$ceil
Yes
$divide
Yes
$exp
Yes
$floor
Yes
$ln
Yes
$log
Yes
$log10
Yes
$mod
Yes
$multiply
Yes
$pow
Yes
$sqrt
Yes
$subtract
Yes
$trunc
Yes
String expressions
Command
Supported
$concat
Yes
$indexOfBytes
Yes
$indexOfCP
Yes
$split
Yes
$strLenBytes
Yes
$strLenCP
Yes
$strcasecmp
Yes
$substr
Yes
$substrBytes
Yes
$substrCP
Yes
$toLower
Yes
$toUpper
Yes
Text search operator
Command
Supported
$meta
No
Array expressions
Command
Supported
$arrayElemAt
Yes
$arrayToObject
Yes
$concatArrays
Yes
$filter
Yes
$indexOfArray
Yes
$isArray
Yes
$objectToArray
Yes
$range
Yes
$reverseArray
Yes
$reduce
Yes
$size
Yes
$slice
Yes
$zip
Yes
$in
Yes
Variable operators
Command
Supported
$map
Yes
$let
Yes
System variables
Command
Supported
$$CURRENT
Yes
$$DESCEND
Yes
$$KEEP
Yes
$$PRUNE
Yes
$$REMOVE
Yes
$$ROOT
Yes
Literal operator
Command
Supported
$literal
Yes
Date expressions
Command
Supported
$dayOfYear
Yes
$dayOfMonth
Yes
$dayOfWeek
Yes
$year
Yes
$month
Yes
$week
Yes
$hour
Yes
$minute
Yes
$second
Yes
$millisecond
Yes
$dateToString
Yes
$isoDayOfWeek
Yes
$isoWeek
Yes
$dateFromParts
Yes
$dateToParts
Yes
$dateFromString
Yes
$isoWeekYear
Yes
Conditional expressions
Command
Supported
$cond
Yes
$ifNull
Yes
$switch
Yes
Data type operator
Command
Supported
$type
Yes
Accumulator expressions
Command
Supported
$sum
Yes
$avg
Yes
$first
Yes
$last
Yes
$max
Yes
$min
Yes
$push
Yes
$addToSet
Yes
$stdDevPop
Yes
$stdDevSamp
Yes
Merge operator
Command
Supported
$mergeObjects
Yes
Data types
Command
Supported
Double
Yes
String
Yes
Object
Yes
Array
Yes
Binary Data
Yes
ObjectId
Yes
Boolean
Yes
Date
Yes
Null
Yes
32-bit Integer (int)
Yes
Timestamp
Yes
64-bit Integer (long)
Yes
MinKey
Yes
MaxKey
Yes
Decimal128
Yes
Regular Expression
Yes
JavaScript
Yes
JavaScript (with scope)
Yes
Undefined
Yes
Indexes and index properties
Indexes
Command
Supported
Single Field Index
Yes
Compound Index
Yes
Multikey Index
Yes
Text Index
No
2dsphere
Yes
2d Index
No
Hashed Index
Yes
Index properties
Command
Supported
TTL
Yes
Unique
Yes
Partial
Only supported with unique indexes
Case Insensitive
No
Sparse
No
Background
Yes
Operators
Logical operators
Command
Supported
$or
Yes
$and
Yes
$not
Yes
$nor
Yes
Element operators
Command
Supported
$exists
Yes
$type
Yes
Evaluation query operators
Command
Supported
$expr
Yes
$jsonSchema
No
$mod
Yes
$regex
Yes
$text
No (Not supported. Use $regex instead.)
$where
No
In the $regex queries, left-anchored expressions allow index search. However, using 'i' modifier (case-insensitivity) and 'm' modifier (multiline) causes the collection scan in all expressions.
When there's a need to include '$' or '|', it is best to create two (or more) regex queries. For example, given the following original query: find({x:{$regex: /^abc$/}), it has to be modified as follows:
find({x:{$regex: /^abc/, x:{$regex:/^abc$/}})
The first part will use the index to restrict the search to those documents beginning with ^abc and the second part will match the exact entries. The bar operator '|' acts as an "or" function - the query find({x:{$regex: /^abc |^def/}) matches the documents in which field 'x' has values that begin with "abc" or "def". To utilize the index, it's recommended to break the query into two different queries joined by the $or operator: find( {$or : [{x: $regex: /^abc/}, {$regex: /^def/}] }).
Array operators
Command
Supported
$all
Yes
$elemMatch
Yes
$size
Yes
Comment operator
Command
Supported
$comment
Yes
Projection operators
Command
Supported
$elemMatch
Yes
$meta
No
$slice
Yes
Update operators
Field update operators
Command
Supported
$inc
Yes
$mul
Yes
$rename
Yes
$setOnInsert
Yes
$set
Yes
$unset
Yes
$min
Yes
$max
Yes
$currentDate
Yes
Array update operators
Command
Supported
$
Yes
$[]
Yes
$[<identifier>]
Yes
$addToSet
Yes
$pop
Yes
$pullAll
Yes
$pull
Yes
$push
Yes
$pushAll
Yes
Update modifiers
Command
Supported
$each
Yes
$slice
Yes
$sort
Yes
$position
Yes
Bitwise update operator
Command
Supported
$bit
Yes
$bitsAllSet
No
$bitsAnySet
No
$bitsAllClear
No
$bitsAnyClear
No
Geospatial operators
Operator
Supported
$geoWithin
Yes
$geoIntersects
Yes
$near
Yes
$nearSphere
Yes
$geometry
Yes
$minDistance
Yes
$maxDistance
Yes
$center
No
$centerSphere
No
$box
No
$polygon
No
Sort operations
When using the findOneAndUpdate operation, sort operations on a single field are supported but sort operations on multiple fields are not supported.
Indexing
The API for MongoDB supports a variety of indexes to enable sorting on multiple fields, improve query performance, and enforce uniqueness.
GridFS
Azure Cosmos DB supports GridFS through any GridFS-compatible MongoDB driver.
Replication
Cosmos DB supports automatic, native replication at the lowest layers. This logic is extended out to achieve low-latency, global replication as well. Cosmos DB does not support manual replication commands.
Retryable Writes
Azure Cosmos DB does not yet support retryable writes. Client drivers must add retryWrites=false to their connection string.
Sharding
Azure Cosmos DB supports automatic, server-side sharding. It manages shard creation, placement, and balancing automatically. Azure Cosmos DB does not support manual sharding commands, which means you don't have to invoke commands such as addShard, balancerStart, moveChunk etc. You only need to specify the shard key while creating the containers or querying the data.
Sessions
Azure Cosmos DB does not yet support server-side sessions commands.
Time-to-live (TTL)
Azure Cosmos DB supports a time-to-live (TTL) based on the timestamp of the document. TTL can be enabled for collections from the Azure portal.
User and role management
Azure Cosmos DB does not yet support users and roles. However, it supports Azure role-based access control (Azure RBAC) and read-write and read-only passwords or keys that can be obtained through the connection string pane in the Azure portal.
Write Concern
Some applications rely on a Write Concern which specifies the number of responses required during a write operation. Due to how Azure Cosmos DB handles replication, all writes are automatically majority quorum by default when using strong consistency. Any write concern specified by the client code is ignored. To learn more, see Using consistency levels to maximize availability and performance article.
Azure Cosmos DB API for MongoDB