Subset

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Relational functions subset

Contents

syntax

  • subset(condition)

definition

subset(condition) results in a new uint32 domain unit with a relation to the entries of the domain unit of the condition, for which the values of the condition argument are true.

description

The subset function generates a subitem, named Nr_OrgEntity. This data item contains the relation towards the domain unit of the condition argument.

The Nr_OrgEntity data item can be used in a lookup function to relate attributes to the new domain, see the example.

applies to

since version

5.15

example

unit<uint32> ZHCities := subset(City/RegionCode == 200)
{
    attribute <string> name := City/Name[Nr_OrgEntity];
}
City/RegionCode City/Name
100 Amsterdam
200 Rotterdam
300 Utrecht
200 Den Haag
400 Eindhoven
null Haarlem
400 Tilburg

domain City, nr of rows = 7

ZHCities/nr_OrgEntity ZHCities/name
1 Rotterdam
3 Den Haag

domain ZHCities, nr of rows = 2

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