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UNPACK


Use this function to extract the value from a single valued collection or list. It is the inverse of the LIST function.


Syntax

UNPACK ( collection/list )


Input
  • collection/list - A collection or list of one entity or attribute instance.


Return type

  • entity instance
  • attribute value of any type


Examples

Suppose the following data model.


Person.namePerson.SequenceNumber
“Bob”654
“Jane”523
“Mary”667
“Rick”500
“Ron”490
“Jenny”765

  • UNPACK ( COLLECT Person.name FROM ALL Person WHERE ( Person.SequenceNumber = MIN ( COLLECT Person.SequenceNumber FROM ALL Person ) ) ) = “Ron”

  • In case a second entry "Ron","490" exists, the expression UNPACK ( COLLECT Person.name FROM ALL Person WHERE ( Person.SequenceNumber = MIN ( COLLECT Person.SequenceNumber FROM ALL Person ) ) ) will fail, because the UNPACK cannot resolve a list with two elements. To solve this the UNIQUE function has to be used: UNPACK ( UNIQUE ( COLLECT Person.name FROM ALL Person WHERE ( Person.SequenceNumber = MIN ( COLLECT Person.SequenceNumber FROM ALL Person ) ) ) ) = "Ron".

  • UNPACK ( COLLECT Person.name FROM ALL Person WHERE ( Person.SequenceNumber = MAX ( COLLECT Person.SequenceNumber FROM ALL Person ) ) ) = “Jenny”

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LIST


Use this function to create a list based on a value. It is the inverse of the UNPACK function.


Syntax

LIST ( attribute/collection )



Inputs
  • attribute - An attribute of any data type.
  • collection/list - A collection or list of values.


Return type

  • a multivalued list with entries of any type


Examples

ExpressionResultType
LIST ( "Blueriq" )[ "Blueriq" ]String (multivalued)
LIST ( 5 )[ 5 ]Integer (multivalued)
LIST ( ? )[]Any (multivalued)


Suppose the following data model.


Person.namePerson.SequenceNumber
“Bob”654
“Jane”523
“Mary”667
“Rick”500
“Ron”490
“Jenny”?
  • LIST ( COLLECT Person.name FROM ALL Person ) = [ "Bob" , "Jane" , "Mary" , "Rick" , "Ron" , "Jenny" ]
    • In this example the LIST function adds no value, as the result of the COLLECT is already a list.
  • LIST ( COLLECT Person.SequenceNumber FROM ALL Person ) = []
    • As Jenny has an unknown sequence number, the result of the COLLECT expression is ?. The LIST function creates an empty list in case the parameter has ? value.

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SIZE


This function determines the size of a collection.


Syntax

SIZE ( collection )



Inputs
  • collection - A collection of attribute or entity instances. This can be an expression or a relation attribute for instance.


Return type

  • integer


Example

Suppose you have a Parent and a Child entity, where Parent has a multivalued relation with Child via the relation Parent.has_Children. With this model the following instances are created:


Parent instanceChild instanceChild.nameChild.hobbies
Parent_1Child_1“Kim”“Reading”, “Dancing”
Parent_1Child_2“Rick”“Tennis”, “Dancing”
Parent_1Child_3“Bob”“Painting”, “Basketball”, “Reading”
Parent_2Child_4“Mary”“Football”


Then:

Active instanceExpressionResultType
Parent_1SIZE ( Parent.has_Children )3Integer
Parent_2SIZE ( Parent.has_Children )1Integer
noneSIZE ( Parent.has_Children )Error
Child_1SIZE ( Child.hobbies )2Integer
Child_3SIZE ( Child.hobbies )3Integer
Child_4SIZE ( Child.hobbies )1Integer

SIZE( ? )0Integer

SIZE and COUNT are similar except for ?:

SIZE ( ? ) results in 0, while COUNT ( ? ) results in ?


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UNIQUE


The UNIQUE function filters duplicate items from a collection. An expression resulting in a collection, never contains duplicate values. A subexpression with the COLLECT statement however, can contain duplicates. See the note on collections and duplicates for more info.


Syntax

 UNIQUE ( collection )


Input
  • collection - A collection of attribute or entity instances.


Return type

  • collection


Examples

Suppose the following model.


Person instancePerson.name
Person_1“Kim”
Person_2“Rick”
Person_3“Bob”
Person_4“Rick”
ExpressionResultTypeNote
COLLECT Person.name FROM ALL Person[ "Kim" , "Rick" , "Bob" ]String (multivalued)A result never contains duplicate values
SIZE ( COLLECT Person.name FROM ALL Person )4IntegerA subexpression can contain duplicate values
SIZE ( UNIQUE ( COLLECT Person.name FROM ALL Person ) )3IntegerThe collection holds three unique values



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SUBSET OF


This function returns TRUE if the items in a collection are all present in another collection.


Syntax

 collection1 SUBSET OF collection2



Inputs
  • collection1 - The collection that is tested to be a subset of the second collection.
  • collection2 - The collection that is tested to hold all the items in the first collection.


Return type

  • Boolean


Venn diagram



Examples

ExpressionResultTypeNote
( 'a' , 'b' , 'c' ) SUBSET OF ( 'a' , 'b' , 'c' , 'd' )TRUEBoolean
( 'a' , 'b' , 'c' , 'd' ) SUBSET OF ( 'a' , 'b' , 'c' )FALSEBoolean
Person.hobbies SUBSET OF [ "Tennis" , "Soccer" , "Music" ]
Given Person.hobbies = [ "Tennis" , "Soccer" ]		TRUEBoolean
Person.hobbies SUBSET OF [ "Tennis" , "Soccer" , "Music" ]
Given Person.hobbies = [ ? ]		?Boolean
Person.hobbies SUBSET OF [ "Tennis" , "Soccer" , ? ]
Given Person.hobbies = [ "Tennis" , "Soccer" ]		FALSEBoolean[ "Tennis" , "Soccer" , ? ] evaluates to [ ? ]
Person.hobbies SUBSET OF [ ? ] = FALSE
( 'a' , 'b' , 'c' ) SUBSET OF ( [ 'a' , 'b' , 'c' , 'd' ] )Error

1 SUBSET OF Address.Numbers

Given Adress.Numbers = ?

FALSEBoolean





Values between single quotes are considered value list items. For backwards compatibility reasons, a comma separated sequence of value list items is treated as a collection. That's why there is no need to enclose the values between square brackets. In fact if you do add the square brackets you create a matrix rather than a list.


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UNION


Adds two collections of the same base type to a new collection.


Syntax

 UNION ( collection1 , collection2 )



Inputs
  • collection1 - First collection to be added to the new collection.
  • collection2 - Second collection to be added to the new collection.


Return type

  • collection


Venn diagram



Examples

Suppose you have a Parent and a Child entity, where Parent has a multivalued relation with Child via the relation Parent.has_Children. With this model the following instances are created:


Parent instanceChild instanceChild.nameChild.hobbies
Parent_1Child_1“Kim”“Reading”, “Dancing”
Parent_1Child_2“Rick”“Tennis”, “Dancing”
Parent_1Child_3“Bob”“Painting”, “Basketball”, “Reading”
Parent_2Child_4“Mary”“Football”
ExpressionResultType
UNION ( Parent[Parent_1].has_Children ,
Parent[Parent_2].Has_Children )		[ Child_1, Child_2 , Child_3, Child_4 ]Collection of Child instances
UNION ( Parent[Parent_1].has_Children.name ,
Parent[Parent_2].Has_Children.name )		[ “Kim”, “Rick”, “Bob”, “Mary” ]String (multivalued)
UNION ( Child[Child_2].hobbies , "Reading" )[ “Tennis”, “Dancing”, “Reading” ]String (multivalued)
UNION ( Child[Child_1].hobbies , Child[Child_2].hobbies )[ “Reading”, “Dancing”, “Tennis” ]String (multivalued)
UNION( ?, [1, 2] )UNKNOWNInteger (multivalued)


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INTERSECTION


This function determines the intersection of two collections. It returns a collection containing the items that are present in both specified collections.


Syntax

INTERSECTION ( collection1 , collection2 )



Inputs
  • collection1, collection2 - Collections to be intersected. These collections must be of the same base type.


Return type

  • collection


Venn diagram



Examples

Suppose the following model. Entity Teacher has a multivalued relation with entity Child via the relation Teacher.teaches_Children.


Teacher instanceChild instanceChild.nameChild.hobbies
Teacher_1Child_1“Kim”“Reading”, “Dancing”
Teacher_1Child_2“Rick”“Tennis”, “Dancing”
Teacher_1Child_3“Bob”“Painting”, “Basketball”, “Reading”
Teacher_2Child_1“Kim”“Reading”, “Dancing”
Teacher_2Child_3“Bob”“Painting”, “Basketball”, “Reading”
Teacher_2Child_4“Mary”“Football”
ExpressionResultType
INTERSECTION ( Teacher[Teacher_1].teaches_Children , Teacher[Teacher_2].teaches_Children )[ Child_1 , Child_3 ]Collection of Child instances
INTERSECTION ( Teacher[Teacher_1].teaches_Children.name , Teacher[Teacher_2].teaches_Children.name )[ "Kim" , "Bob" ]String (multivalued)
INTERSECTION ( Child[Child_1].hobbies , Child[Child_3].hobbies )[ "Reading" ]String (multivalued)
INTERSECTION ( Child[Child_2].hobbies , Child[Child_3].hobbies )[ ]String (multivalued)
INTERSECTION( ?, [ 1, 2 ] )UNKNOWNInteger (multivalued)


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DIFFERENCE


This function returns a collection containing all the items from collection1 that are not present in collection2.


Syntax

DIFFERENCE ( collection1 , collection2 )


Inputs
  • collection1, collection2 - Collections to be compared. These collections must be of the same base type.


Return type

  • collection


Venn diagram



Examples

ExpressionResultType
DIFFERENCE ( [ "a", "b", "c"] , [ "c", "d", "e" ] )[ "a" , "b" ]String (multivalued)
DIFFERENCE ( [ "nv" , "bv" ] , [ "NV" ] )[ "bv" ]String (multivalued)
DIFFERENCE ( 1 , 1 )[ ]Integer (multivalued)
DIFFERENCE( [ 1, 2 ], ? )?Integer (multivalued)


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SYMMETRIC_DIFFERENCE


This function determines the symmetric difference between two collections. It returns a collection with the elements of the provided collections which are in either one of the collections, but not in both.


Syntax

SYMMETRIC_DIFFERENCE ( collection1 , collection2 )


Inputs
  • collection1, collection2 - Collections to be compared. These collections must be of the same base type.


Return type

  • collection


Venn diagram



Examples

ExpressionResultType
SYMMETRIC_DIFFERENCE ( [ "a" , "b" , "c" ] , [ "c" , "d" , "e" ] )[ "a", "b", "d", "e" ]String (multivalued)
SYMMETRIC_DIFFERENCE ( [ "nv" , "bv" ] , [ "NV" ] )[ "bv" ]String (multivalued)
SYMMETRIC_DIFFERENCE ( 1 , 1 )[ ]Integer (multivalued)



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A note on collections and duplicates


An expression resulting in a collection does not contain duplicates. Please be aware however, that intermediary results of a COLLECT statement can contain duplicates. You have to be aware of this when using the SIZE or UNPACK function, or when using TSL.

This is best illustrated with the following examples.

Person instancePerson.NamePerson.Age
Person_1Kim24
Person_2Rick25
Person_3Bob25
ExpressionResultTypeNote
COLLECT Person.Age FROM ALL Person[ 24 , 25 ]String (multivalued)
SIZE ( COLLECT Person.Age FROM ALL Person )3IntegerThe intermediary collection is [ 24, 25, 25 ]

 TSL:

The ages present are: [[[ COLLECT Person.Age FROM ALL Person ]]].

The ages present are: 24, 25, 25.StringThe intermediary collection is [ 24, 25, 25 ]
SIZE ( UNIQUE ( COLLECT Person.Age FROM ALL Person ) )2IntegerThe duplicates in the intermediary collection are filtered by the UNIQUE function


Now an example with the UNPACK function. We leave out the first instance from the previous example.

Person instancePerson.NamePerson.Age
Person_2Rick25
Person_3Bob25
ExpressionResultTypeNote
COLLECT Person.Age FROM ALL Person[ 25 ]Integer (multivalued)
UNPACK ( COLLECT Person.Age FROM ALL Person )Error
The collection contains 2 elements [ 25 , 25 ]
UNPACK ( UNIQUE ( COLLECT Person.Age FROM ALL Person ) )25



 Only the intermediary results of a COLLECT statement can contain duplicates. The functions UNIQUE, UNION, INTERSECTION, DIFFERENCE and SYMMETRIC_DIFFERENCE always return collections without duplicates.


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