What for Cardinality is used?

Question

Hi,
Explain me about the <b>cardinality</b> and what foor it is used?
Thanks

Answer 1

Hi suresh..
<b>Cardinality</b>
http://wendtstud1.hpi.uni-potsdam.de/sysmod-seminar/SS2005/elaborations/14-WebDynpro-Dataflow.pdf
The cardinality of the subset of node elements that can be selected is usually 0..1, that is, a maximum of one node element can be selected.
In general, the node selection can consist of any subset of all node elements that are available in a node. If several node elements can be selected, this is know as multiple selection (selection=0..n or 1..n).
Any node or attribute that has the context root node as its immediate parent, is known as an independent node or attribute.
Any node or attribute that has some other node as its immediate parent, is known as a dependent node or attribute.
All context nodes are collections.
A node collection is composed of elements, where an element is an aggregation of the node’s immediate children (attributes and/or other nodes).
The cardinality property controls the number of elements a node collection may hold at runtime.
Every context node has a property called Cardinality. This property is composed of two values that taken together, describe the maximum and minimum number of elements the node collection may hold at runtime.
?? Cardinality Minimum: 0 or 1
?? Cardinality Maximum: 1 or n
Therefore, there are four possible cardinality values (specified as <Min>..<Max>)
?? 0..1 Zero or one elements permitted
?? 0..n Zero or more elements permitted
?? 1..1 One and only one element permitted
?? 1..n One or more elements permitted
initializeLeadSelection= true:
The lead selection automatically points to the node element at position 0, after at least one node element was added to a node collection that was previously empty (for example, by calling the bind or addElement methods).
If the node selection’s cardinality permits it, the lead selection can subsequently be reset using setLeadSelection(NO_SELECTION).
initializeLeadSelection= false:
The lead selection is not automatically initialized unless the node selection’s cardinality requires it.
Hop this will help..
Urs GS