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CX_FORMULA_ATTRIBUTE - Calculated attribute

CX_FORMULA_ATTRIBUTES

Class hierarchy
Description:

A calculated attribute allows the contents of a slot to be filled by a formula. It also provides a more detailed description of this field.

An example of this is the definition of an article "carpet", which, in addition to a length and width specification, contains the data field "carpet size", which is calculated from the first two sizes according to the formula "area = length x width". This formula is stored once in the system and can be used in a specific context by means of a formula attribute.

Example: Different area specifications (e.g. carpet size and floor space) based on a slot area which contains the formula "area = length x width

A CX_FORMULA_ATTRIBUTE can be given the parameters for its own formula, e.g. sub-formulae such as (l=) a + 5, where a is a slot in the CX_FORMULA_ATTRIBUTE. a could therefore be a conditioned bag itself: attribute area = attribute length * attribute width

Code example: 
// Create the formula attribute with formula: volume=width*height*depth
Var(formulaAttribute, formula)
CreateTransObject(CX_FORMULA_ATTRIBUTE) -> formulaAttribute
CreateTransObject(CX_FORMULA) -> formula
"width*height*depth" // = volume
formula Put

"volume" formulaAttribute Put(NameMA())  // which slot should be calculated?
formula formulaAttribute Link(formula)   // how should the slot's value be calculated?

// Wrap our formula attribute inside an attribute set
Var(attributeSet)
CreateTransObject(CX_ATTRIBUTE_SET) -> attributeSet
formulaAttribute attributeSet Link(attributes)


// Create the item to calculate the attribute for
Var(item)
CreateTransObject(CX_ITEM) -> item
attributeSet item Link(attributeSet) // add our formula attribute to this item

// Fill the dependent variables (slots)
10m item Put(width)
5m item Put(height)
5cm item Put(depth)


// Put the item itself into the plug space (formula variables are searched in the plug space)
// and calculate the volume based on the above properties.
[ item ] PlugSpace
item Copy(volume) // -> 2500 l

List of methods (MDI)
Function MA* Parameters Return Brief description
IsValueAttribute INTEGER Is this attribute a preset attribute?
GetInputAccessPaths
233188  		 VECTOR<STRING>Determine the access paths that occur in the formula.
GetInputVarNames (OBJECT.)VECTOR<STRING>Determine the slots that occur in the formula.
SanityCheck INTEGER Check for consistency of the object
AttributeDescription *
AttributeID STRING
CalculationSubterms VECTOR Determining the slot names that occur in a formula
CheckValue INTEGER
ClassFilter STRING, INTEGER OBJECT This object, if it corresponds to a certain class
ConditionedFilter STRING OBJECT
ConditionedFilter2 OBJECT OBJECT
ConvertObject OBJECT ANY converts the transferred object into a value that corresponds to the type of the attribute; in the case of a result of the type CX_NUMERIC and derived, the decimal places are taken from the attribute value
CreatePersistentTable OBJECT creates a table for enumerations or discrete values and connects it to the attribute object
Deleted INTEGER Object marked as deleted?
DeletePersistentTable deletes a table linked to the attribute for enumerations or discrete values
Description STRING Name of this object
ElementOf OBJECT OBJECT
GetDomain INTEGER Domain of this object
GetSiblings COLLECTION All siblings of this object
GetSiblings2 COLLECTION All siblings of this object
GetSlotEntries VECTOR<object>VECTOR<object></ob Return of internal information about slots
GetValue STRING, STRING, INTEGER OBJECT Dummy function
HasConstraint * Validity available?
LastUpdate OBJECT Date of the last write access
LastUser INTEGERINTEGER User who last had write access to the object
LimitedValuesMA *
link OBJECT Add this object to the list of objects with validity
Name STRING Name of the slot that the attribute explains
NameMA * Name or (internal) number of the slot that the attribute explains in more detail
NextValidObject OBJECT Subsequent validity object in time
NullValue ANY Null value of the type of the attribute value
PreviousValidObject OBJECT Previous validity object in time
RefTypeID INTEGERINTEGER
RestrictedValidity * Area of validity limited?
SetDomain INTEGERINTEGER, INTEGER Set domain
ShortName STRING Short name of this object
Siblings * Objects with validity
SpanDateValidity * Period of validity
SpecifierID STRING
Type STRING Return of the data type held in the slot
TypeID INTEGERINTEGER Returns the ID number of the data type held in the slot
string INTEGERINTEGER CX_STRING Returns the string representation of the object
UnconditionalValue * Value of the slot, constraints are not considered
UnconditionalValueObject ANY Value of the slot, constraints are not considered
UniqueID STRING Content of the fixed data field "uniqueID
Unlink Remove this object from the list of objects with validity
Unlink2 Remove this object from the list of objects with validity
Valid OBJECT INTEGERINTEGER Check validity
ValidSince OBJECT Start of validity period
ValidToday INTEGERINTEGER Valid today?
ValidUntil OBJECT End of validity period
Value * Value of the slot, when the slot is issued, the calculated value is tested against constraints
Value Export INTEGERINTEGER STRING Value of the slot, formatted as string
ValueObject ANY Value of the slot, the calculated value tested against constraints
VerifySiblings INTEGERINTEGER Check ring of exchange objects

* MA = Member Access function,
grey background = inherited function

Data directory (DDI)
Data field Type Reference class I* Brief description
formula POINTER CX_FORMULA The formula
attribute INTEGERINTEGER The (internal) number of the slot that the attribute explains in more detail
attributeEnum ENUMSHORT Type
constraint POINTER CX_FORMULA Validity
uniqueID STRING * Unique key
validity POINTER CX_VALIDITY Validity period of the object

* I = Indexable data field,
grey background = inherited data field

Use in AppsWH
Module Brief description
attrfedt.mod Calculated features Editing module