kddml.Core.QueryElement.Expression.Expression Class Reference
Inheritance diagram for kddml.Core.QueryElement.Expression.Expression:
List of all members.
Detailed Description
An expression as used in KDD Query. This object is used to represent language expressions. Expressions are similar to conditions, but they return a scalar (i.e., a number of string) instead of a boolean value. Expression admits a sequential statement (element SEQ TERM), including basic operations (such as sum, multiplication, subtraction, division of numbers and concatenation of strings) on primitive terms of the expression.
Also a conditional statement (element IF TERM) is admitted. It is used to evaluate a then statement or an (optional) else statement according to a condition.
Finally, the element BASE TERM is used to provide numeric/string constants or table attribute names (as for conditions, with the special symbol "@" in the value attribute of the BASE TERM element we denote an input table column).
Title: KDDML
Description: Knowledge Discovery in Database Environment
Copyright: Copyright (c) 2003-2005
Company: Universita' di Pisa - Dipartimento di Informatica
- Author:
- Andrea Romei (romei@di.unipi.it)
Sandra Zimei
- Version:
- 2.0.16
Member Function Documentation
abstract String kddml.Core.QueryElement.Expression.Expression.evalExpr |
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throws KDDMLCoreException [pure virtual] |
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KDDMLObjectType kddml.Core.QueryElement.Expression.Expression.getType |
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