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ISNULLThis function checks Checks whether a value is unknown. Syntax
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IFUNKNOWNAn alternative notation of the ISUNKOWN function, which increases readability especially for long expressions. This function replaces a value if that value is unknown. The IFUNKNOWN function takes precendence over any other binary operator (except for the "NOT" operator). Syntax
Return type
Examples Suppose the following data model. | |||
| Person.name | Person.SequenceNumber | Person.HasDrivingLicense | |
| “Bob” | 654 | true | |
| “Jane” | ? | true | |
| “Mary” | 667 | false | |
| “Rick” | ? | ? | |
| “Ron” | ? | false | |
| “Jenny” | 765 | true |
| Person.name | Person.SequenceNumber |
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| “Bob” | 654 |
| “Jane” | ? |
| Active Person | Expression | Result | Type |
|---|---|---|---|
| Bob | ISNULL ( Person.SequenceNumber ) | FALSE | Booleanboolean |
| Jane | ISNULL ( Person.SequenceNumber ) | TRUE | Boolean |
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ISUNKNOWN
This function replaces a value if that value is unknown.
Syntax
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ISUNKNOWN ( expression , value ) |
- expression- Expression of which the value has to be returned if that value is known.
- value - Value to return if the expression value is unknown.
Return type
- any type, equals the expression type
Examples
Suppose the following data model.
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Both parameters of the
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Both parameters of the
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IS A
Use this function to check the type of an instance. The function returns TRUE if the selected instance is of the specified entity.
Syntax
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instance IS A entity_name |
- instance - Instance to check.
- entity_name - Name of the entity as string.
Return type
- boolean
Examples
Suppose a domain model in which there is a singleton entity Residence that has a multivalued relation hasRooms with Room. Room is the base entity for singleton Kitchen and not singletons Bedroom and Bathroom.
If you want to determine the number of bedrooms is the residence:
COUNT ( COLLECT Room FROM Residence.hasRooms WHERE ( Room IS A “Bedroom” ) )
If you want to determine the number of bathrooms is the residence:
COUNT ( COLLECT Room FROM Residence.hasRooms WHERE ( Room IS A “Bathroom” ) )
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TYPE OF
Use this function to determine the type of an instance. The function returns the name of the entity.
Syntax
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TYPE OF base_entity |
- base_entity - Name of the instance's base entity.
Return type
- string
Examples
Suppose a domain model in which there is a singleton entity Residence that has a multivalued relation hasRooms with Room. Room is the base entity for singleton Kitchen and not singletons Bedroom and Bathroom.
- for the
Kitcheninstance the expression( TYPE OF Room ) = “Kitchen” - for the
Bedroominstances the expression( TYPE OF Room ) = “Bedroom”
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ISACTIVE
Use this function to determine if an instance of a specific type is currently active.
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ISACTIVE instances [WHERE condition] |
- instances - instances to search
- condition - optional condition to limit the collection of instances to check
Return type
boolean - TRUE if one of the instances is active, FALSE otherwise
UI Text Box type note Singletons are always active, so
ISACTIVE<singleton> will always returnTRUE
Examples
Suppose the following data model.
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GUID
This function is able to generate a globally unique identifier which can later be used to uniquely mark and recognize a desired element.
The GUIDs are represented as 32 hexadecimal digits, displayed in five groups separated by hyphens, in the form 8-4-4-4-12 for a total of 36 characters.
Syntax
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GUID() |
Return type
String - the generated GUID
Examples
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Overview
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