Class Aggregand

Expression which is used to "group by" in an aggregation from one table to another.

Inheritance
Object
Expression
Expression<Aggregand, Aggregation>
Aggregand
Inherited Members
Namespace: Mangrove.MetricSetSyntaxTree.ExpressionNodes
Assembly: MetricSetSyntaxTree.dll
Syntax
public class Aggregand : Expression<Aggregand, Aggregation>, IVisitable<IExpressionVisitor>, ICloneable<Aggregand, Aggregation, Expression>, ICloneable<Expression>, IDirectedAcyclicGraph<Expression>
Remarks

To motivate aggregands, consider the SQL statement:

WITH BASE_TABLE AS ( SELECT State, City, Population FROM DATA_SOURCE ), STATEWIDE_TABLE AS ( SELECT State, SUM(Population) AS Population FROM BASE_TABLE GROUP BY State )

In generating the state-wide table, the GROUP BY clause refers to the State column in BASE_TABLE. In Mangrove, an Aggregand provides this link.

Constructors

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Aggregand(Aggregation, Expression)

Declaration
public Aggregand(Aggregation table, Expression source)
Parameters
Type Name Description
Aggregation table
Expression source

Properties

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Parents

Declaration
[JsonIgnore]
public override IReadOnlyList<Expression> Parents { get; }
Property Value
Type Description
IReadOnlyList<Expression>
Overrides
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Source

One of the columns you "group by" to get from the Source table to the "target" table.

Declaration
public Expression Source { get; }
Property Value
Type Description
Expression

Methods

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Accept(IExpressionVisitor)

Declaration
public override void Accept(IExpressionVisitor visitor)
Parameters
Type Name Description
IExpressionVisitor visitor
Overrides
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Clone(Aggregation, IReadOnlyList<Expression>)

Declaration
public override Aggregand Clone(Aggregation table, IReadOnlyList<Expression> parents)
Parameters
Type Name Description
Aggregation table
IReadOnlyList<Expression> parents
Returns
Type Description
Aggregand
Overrides
Mangrove.MetricSetSyntaxTree.Expression<Mangrove.MetricSetSyntaxTree.ExpressionNodes.Aggregand, Mangrove.MetricSetSyntaxTree.TableNodes.Aggregation>.Clone(Mangrove.MetricSetSyntaxTree.TableNodes.Aggregation, System.Collections.Generic.IReadOnlyList<Mangrove.MetricSetSyntaxTree.Expression>)

Implements

Extension Methods