object Accumulators
Builders for accumulators used in the group pipeline stage of an aggregation pipeline.
- Since
1.0
- See also
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- Accumulators
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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
$accumulator
pipeline stageCreates an
$accumulator
pipeline 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
$accumulator
pipeline 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
$accumulator
pipeline stageCreates an
$accumulator
pipeline 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
$accumulator
pipeline 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
$accumulator
pipeline stageCreates an
$accumulator
pipeline 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
$accumulator
pipeline 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
$accumulator
pipeline stageCreates an
$accumulator
pipeline 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
$accumulator
pipeline 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
$group
operation 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
$group
operation 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
$group
operation representing the average of the values of the given expression when applied to all members of the group.Gets a field name for a
$group
operation 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 bottom[OutExpression](fieldName: String, sortBy: Bson, outExpression: OutExpression): BsonField
Returns a combination of a computed field and an accumulator that produces a value of the given
outExpression
computed for the bottom element within a group sorted according to the providedsort
specification.Returns a combination of a computed field and an accumulator that produces a value of the given
outExpression
computed for the bottom element within a group sorted according to the providedsort
specification.- OutExpression
The type of the output expression.
- fieldName
The field computed by the accumulator.
- sortBy
The sort specification. The syntax is identical to the one expected by Aggregates.sort.
- outExpression
The output expression.
- returns
The requested BsonField.
- Since
4.7
- Note
Requires MongoDB 5.2 or greater
- See also
- def bottomN[OutExpression, NExpression](fieldName: String, sortBy: Bson, outExpression: OutExpression, nExpression: NExpression): BsonField
Returns a combination of a computed field and an accumulator that produces a BSON
Array
of values of the givenoutExpression
computed for the bottomN
elements within a group sorted according to the providedsort
specification, whereN
is the positive integral value of thenExpression
.Returns a combination of a computed field and an accumulator that produces a BSON
Array
of values of the givenoutExpression
computed for the bottomN
elements within a group sorted according to the providedsort
specification, whereN
is the positive integral value of thenExpression
.- OutExpression
The type of the output expression.
- NExpression
The type of the limiting expression.
- fieldName
The field computed by the accumulator.
- sortBy
The sort specification. The syntax is identical to the one expected by Aggregates.sort.
- outExpression
The output expression.
- nExpression
The expression limiting the number of produced values.
- returns
The requested BsonField.
- Since
4.7
- Note
Requires MongoDB 5.2 or greater
- See also
- def clone(): AnyRef
- Attributes
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- @throws(classOf[java.lang.CloneNotSupportedException]) @native() @IntrinsicCandidate()
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- def first[TExpression](fieldName: String, expression: TExpression): BsonField
Gets a field name for a
$group
operation representing the value of the given expression when applied to the first member of the group.Gets a field name for a
$group
operation 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
- def firstN[InExpression, NExpression](fieldName: String, inExpression: InExpression, nExpression: NExpression): BsonField
Returns a combination of a computed field and an accumulator that produces a BSON
Array
of values of the giveninExpression
computed for the firstN
elements within a presorted group, whereN
is the positive integral value of thenExpression
.Returns a combination of a computed field and an accumulator that produces a BSON
Array
of values of the giveninExpression
computed for the firstN
elements within a presorted group, whereN
is the positive integral value of thenExpression
.- InExpression
The type of the input expression.
- NExpression
The type of the limiting expression.
- fieldName
The field computed by the accumulator.
- inExpression
The input expression.
- nExpression
The expression limiting the number of produced values.
- returns
The requested BsonField.
- Since
4.7
- Note
Requires MongoDB 5.2 or greater
- See also
- final def getClass(): Class[_ <: AnyRef]
- Definition Classes
- AnyRef → Any
- Annotations
- @native() @IntrinsicCandidate()
- def hashCode(): Int
- Definition Classes
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- Annotations
- @native() @IntrinsicCandidate()
- final def isInstanceOf[T0]: Boolean
- Definition Classes
- Any
- def last[TExpression](fieldName: String, expression: TExpression): BsonField
Gets a field name for a
$group
operation representing the value of the given expression when applied to the last member of the group.Gets a field name for a
$group
operation 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 lastN[InExpression, NExpression](fieldName: String, inExpression: InExpression, nExpression: NExpression): BsonField
Returns a combination of a computed field and an accumulator that produces a BSON
Array
of values of the giveninExpression
computed for the lastN
elements within a presorted group whereN
is the positive integral value of thenExpression
.Returns a combination of a computed field and an accumulator that produces a BSON
Array
of values of the giveninExpression
computed for the lastN
elements within a presorted group whereN
is the positive integral value of thenExpression
.- InExpression
The type of the input expression.
- NExpression
The type of the limiting expression.
- fieldName
The field computed by the accumulator.
- inExpression
The input expression.
- nExpression
The expression limiting the number of produced values.
- returns
The requested BsonField.
- Since
4.7
- Note
Requires MongoDB 5.2 or greater
- See also
- def max[TExpression](fieldName: String, expression: TExpression): BsonField
Gets a field name for a
$group
operation representing the maximum of the values of the given expression when applied to all members of the group.Gets a field name for a
$group
operation 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 maxN[InExpression, NExpression](fieldName: String, inExpression: InExpression, nExpression: NExpression): BsonField
Returns a combination of a computed field and an accumulator that produces a BSON
Array
ofN
largest values of the giveninExpression
, whereN
is the positive integral value of thenExpression
.Returns a combination of a computed field and an accumulator that produces a BSON
Array
ofN
largest values of the giveninExpression
, whereN
is the positive integral value of thenExpression
.- InExpression
The type of the input expression.
- NExpression
The type of the limiting expression.
- fieldName
The field computed by the accumulator.
- inExpression
The input expression.
- nExpression
The expression limiting the number of produced values.
- returns
The requested BsonField.
- Since
4.7
- Note
Requires MongoDB 5.2 or greater
- See also
- def mergeObjects[TExpression](fieldName: String, expression: TExpression): BsonField
Gets a field name for a
$group
operation representing the result of merging the fields of the documents.Gets a field name for a
$group
operation 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
$group
operation representing the minimum of the values of the given expression when applied to all members of the group.Gets a field name for a
$group
operation 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
- def minN[InExpression, NExpression](fieldName: String, inExpression: InExpression, nExpression: NExpression): BsonField
Returns a combination of a computed field and an accumulator that produces a BSON
Array
ofN
smallest values of the giveninExpression
, whereN
is the positive integral value of thenExpression
.Returns a combination of a computed field and an accumulator that produces a BSON
Array
ofN
smallest values of the giveninExpression
, whereN
is the positive integral value of thenExpression
.- InExpression
The type of the input expression.
- NExpression
The type of the limiting expression.
- fieldName
The field computed by the accumulator.
- inExpression
The input expression.
- nExpression
The expression limiting the number of produced values.
- returns
The requested BsonField.
- Since
4.7
- Note
Requires MongoDB 5.2 or greater
- 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
$group
operation 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
$group
operation 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
$group
operation 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
$group
operation 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
$group
operation 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
$group
operation 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
$group
operation representing the sum of the values of the given expression when applied to all members of the group.Gets a field name for a
$group
operation 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
- Definition Classes
- AnyRef
- def toString(): String
- Definition Classes
- AnyRef → Any
- def top[OutExpression](fieldName: String, sortBy: Bson, outExpression: OutExpression): BsonField
Returns a combination of a computed field and an accumulator that produces a value of the given
outExpression
computed for the top element within a group sorted according to the providedsort
specification.Returns a combination of a computed field and an accumulator that produces a value of the given
outExpression
computed for the top element within a group sorted according to the providedsort
specification.- OutExpression
The type of the output expression.
- fieldName
The field computed by the accumulator.
- sortBy
The sort specification. The syntax is identical to the one expected by Aggregates.sort.
- outExpression
The output expression.
- returns
The requested BsonField.
- Since
4.7
- Note
Requires MongoDB 5.2 or greater
- See also
- def topN[OutExpression, NExpression](fieldName: String, sortBy: Bson, outExpression: OutExpression, nExpression: NExpression): BsonField
Returns a combination of a computed field and an accumulator that produces a BSON
Array
of values of the givenoutExpression
computed for the topN
elements within a group sorted according to the providedsort
specification, whereN
is the positive integral value of thenExpression
.Returns a combination of a computed field and an accumulator that produces a BSON
Array
of values of the givenoutExpression
computed for the topN
elements within a group sorted according to the providedsort
specification, whereN
is the positive integral value of thenExpression
.- OutExpression
The type of the output expression.
- NExpression
The type of the limiting expression.
- fieldName
The field computed by the accumulator.
- sortBy
The sort specification. The syntax is identical to the one expected by Aggregates.sort.
- outExpression
The output expression.
- nExpression
The expression limiting the number of produced values.
- returns
The requested BsonField.
- Since
4.7
- Note
Requires MongoDB 5.2 or greater
- See also
- final def wait(arg0: Long, arg1: Int): Unit
- Definition Classes
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- @throws(classOf[java.lang.InterruptedException])
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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: