object Accumulators
Builders for accumulators used in the group pipeline stage of an aggregation pipeline.
- Since
1.0
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- def accumulator(fieldName: String, initFunction: String, initArgs: Seq[String], accumulateFunction: String, accumulateArgs: Seq[String], mergeFunction: String, finalizeFunction: String, lang: String): BsonField
Creates an
$accumulatorpipeline stageCreates an
$accumulatorpipeline stage- fieldName
the field name
- initFunction
a function used to initialize the state
- initArgs
init function’s arguments (may be null)
- accumulateFunction
a function used to accumulate documents
- accumulateArgs
additional accumulate function’s arguments (may be null). The first argument to the function is ‘state’.
- mergeFunction
a function used to merge two internal states, e.g. accumulated on different shards or threads. It returns the resulting state of the accumulator.
- finalizeFunction
a function used to finalize the state and return the result (may be null)
- lang
a language specifier
- returns
the
$accumulatorpipeline stage
- Since
1.2
- Note
Requires MongoDB 4.4 or greater
- See also
- def accumulator(fieldName: String, initFunction: String, initArgs: Seq[String], accumulateFunction: String, accumulateArgs: Seq[String], mergeFunction: String, finalizeFunction: String): BsonField
Creates an
$accumulatorpipeline stageCreates an
$accumulatorpipeline stage- fieldName
the field name
- initFunction
a function used to initialize the state
- initArgs
init function’s arguments (may be null)
- accumulateFunction
a function used to accumulate documents
- accumulateArgs
additional accumulate function’s arguments (may be null). The first argument to the function is ‘state’.
- mergeFunction
a function used to merge two internal states, e.g. accumulated on different shards or threads. It returns the resulting state of the accumulator.
- finalizeFunction
a function used to finalize the state and return the result (may be null)
- returns
the
$accumulatorpipeline stage
- Since
1.2
- Note
Requires MongoDB 4.4 or greater
- See also
- def accumulator(fieldName: String, initFunction: String, accumulateFunction: String, mergeFunction: String, finalizeFunction: String): BsonField
Creates an
$accumulatorpipeline stageCreates an
$accumulatorpipeline stage- fieldName
the field name
- initFunction
a function used to initialize the state
- accumulateFunction
a function used to accumulate documents
- mergeFunction
a function used to merge two internal states, e.g. accumulated on different shards or threads. It returns the resulting state of the accumulator.
- finalizeFunction
a function used to finalize the state and return the result (may be null)
- returns
the
$accumulatorpipeline stage
- Since
1.2
- Note
Requires MongoDB 4.4 or greater
- See also
- def accumulator(fieldName: String, initFunction: String, accumulateFunction: String, mergeFunction: String): BsonField
Creates an
$accumulatorpipeline stageCreates an
$accumulatorpipeline stage- fieldName
the field name
- initFunction
a function used to initialize the state
- accumulateFunction
a function used to accumulate documents
- mergeFunction
a function used to merge two internal states, e.g. accumulated on different shards or threads. It returns the resulting state of the accumulator.
- returns
the
$accumulatorpipeline stage
- Since
1.2
- Note
Requires MongoDB 4.4 or greater
- See also
- def addToSet[TExpression](fieldName: String, expression: TExpression): BsonField
Gets a field name for a
$groupoperation representing all unique values that results from applying the given expression to each document in a group of documents that share the same group by key.Gets a field name for a
$groupoperation representing all unique values that results from applying the given expression to each document in a group of documents that share the same group by key.- TExpression
the expression type
- fieldName
the field name
- expression
the expression
- returns
the field
- See also
- final def asInstanceOf[T0]: T0
- Definition Classes
- Any
- def avg[TExpression](fieldName: String, expression: TExpression): BsonField
Gets a field name for a
$groupoperation representing the average of the values of the given expression when applied to all members of the group.Gets a field name for a
$groupoperation representing the average of the values of the given expression when applied to all members of the group.- TExpression
the expression type
- fieldName
the field name
- expression
the expression
- returns
the field
- See also
- def clone(): AnyRef
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- def first[TExpression](fieldName: String, expression: TExpression): BsonField
Gets a field name for a
$groupoperation representing the value of the given expression when applied to the first member of the group.Gets a field name for a
$groupoperation representing the value of the given expression when applied to the first member of the group.- TExpression
the expression type
- fieldName
the field name
- expression
the expression
- returns
the field
- See also
- final def getClass(): Class[_ <: AnyRef]
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- final def isInstanceOf[T0]: Boolean
- Definition Classes
- Any
- def last[TExpression](fieldName: String, expression: TExpression): BsonField
Gets a field name for a
$groupoperation representing the value of the given expression when applied to the last member of the group.Gets a field name for a
$groupoperation representing the value of the given expression when applied to the last member of the group.- TExpression
the expression type
- fieldName
the field name
- expression
the expression
- returns
the field
- See also
- def max[TExpression](fieldName: String, expression: TExpression): BsonField
Gets a field name for a
$groupoperation representing the maximum of the values of the given expression when applied to all members of the group.Gets a field name for a
$groupoperation representing the maximum of the values of the given expression when applied to all members of the group.- TExpression
the expression type
- fieldName
the field name
- expression
the expression
- returns
the field
- See also
- def mergeObjects[TExpression](fieldName: String, expression: TExpression): BsonField
Gets a field name for a
$groupoperation representing the result of merging the fields of the documents.Gets a field name for a
$groupoperation representing the result of merging the fields of the documents. If documents to merge include the same field name, the field, in the resulting document, has the value from the last document merged for the field.- TExpression
the expression type
- fieldName
the field name
- expression
the expression
- returns
the field
- Since
4.4
- See also
- def min[TExpression](fieldName: String, expression: TExpression): BsonField
Gets a field name for a
$groupoperation representing the minimum of the values of the given expression when applied to all members of the group.Gets a field name for a
$groupoperation representing the minimum of the values of the given expression when applied to all members of the group.- TExpression
the expression type
- fieldName
the field name
- expression
the expression
- returns
the field
- See also
- final def ne(arg0: AnyRef): Boolean
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- final def notify(): Unit
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- def push[TExpression](fieldName: String, expression: TExpression): BsonField
Gets a field name for a
$groupoperation representing an array of all values that results from applying an expression to each document in a group of documents that share the same group by key.Gets a field name for a
$groupoperation representing an array of all values that results from applying an expression to each document in a group of documents that share the same group by key.- TExpression
the expression type
- fieldName
the field name
- expression
the expression
- returns
the field
- See also
- def stdDevPop[TExpression](fieldName: String, expression: TExpression): BsonField
Gets a field name for a
$groupoperation representing the sample standard deviation of the values of the given expression when applied to all members of the group.Gets a field name for a
$groupoperation representing the sample standard deviation of the values of the given expression when applied to all members of the group.Use if the values encompass the entire population of data you want to represent and do not wish to generalize about a larger population.
- TExpression
the expression type
- fieldName
the field name
- expression
the expression
- returns
the field
- Since
1.1
- Note
Requires MongoDB 3.2 or greater
- See also
- def stdDevSamp[TExpression](fieldName: String, expression: TExpression): BsonField
Gets a field name for a
$groupoperation representing the sample standard deviation of the values of the given expression when applied to all members of the group.Gets a field name for a
$groupoperation representing the sample standard deviation of the values of the given expression when applied to all members of the group.Use if the values encompass a sample of a population of data from which to generalize about the population.
- TExpression
the expression type
- fieldName
the field name
- expression
the expression
- returns
the field
- Since
1.1
- Note
Requires MongoDB 3.2 or greater
- See also
- def sum[TExpression](fieldName: String, expression: TExpression): BsonField
Gets a field name for a
$groupoperation representing the sum of the values of the given expression when applied to all members of the group.Gets a field name for a
$groupoperation representing the sum of the values of the given expression when applied to all members of the group.- TExpression
the expression type
- fieldName
the field name
- expression
the expression
- returns
the field
- See also
- final def synchronized[T0](arg0: => T0): T0
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- Deprecated
This is the documentation for the MongoDB Scala driver.
Driver structure
The mongodb scala driver.
To get started you need a MongoClient instance, either from a connection string or via a org.mongodb.scala.MongoClientSettings.
Notable packages include: