This is the old version of our wiki. We advice to visit: https://www.geodms.nl

From ObjectVision

Relational functions union_data

syntax

• union_data(domainunit, a, b, .. n)

definition

union_data(domainunit, a, b, .. n) results in a new attribute with as domain unit the first argument: domainunit.

The resulting attribute contains the values of the data items a, b, .., n.

description

The first argument domainunit, is often made with the union_unit function.

The union_data function results in an attribute with as values unit the values units of data items a, b, ..n and as domain unit the first argument of the function (domainunit).

union_data(newdomain, att_old_domain) can be used to convert attributes from a source to a target domain unit.

applies to

• unit domainunit with value type from the group CanBeDomainUnit
• data items a, b, ... n with Numeric, Point, uint2, uint4, bool or string value type

conditions

• The values unit of data items a, b, ... n must match.

since version

5.15

example

unit<uint32> HollandCity := union_unit(NHCity, ZHCity)
{ 
   attribute<string> name := union_data(., NHCity/name, ZH/City/name); 
}

domain HollandCity, nr of rows = 8

domain NHCity, nr of rows = 3

domain ZHCity, nr of rows = 5

see also

• union_unit