Context

Definition

The data used in the component or in the view are stored in the context. Read-write access to this data is available using the controllers as a starting point.

Structure

The data from the contexts is managed in a hierarchical structure. Each context has a root node, underneath which the individual data fields (attributes) are stored in a tree structure. You create this tree structure according to the structure of your application.

Each node contains data fields that represent one of the following:

  • An individual instance of an object type
  • A table of instances.

This property of a node is known as its cardinality. The following table summarizes the possible cardinalities for a node:

Cardinality

Description

1:1

The node contains only one element instance, which is instantiated automatically.

0:1

The node contains only one element instance, which must not be instantiated.

1:n

The node can contain multiple element instances, of which at least one must always be instantiated (and is instantiated automatically).

0:n

The node can contain multiple element instances, of which none have to be instantiated.

Further information about this and other properties of context nodes is available in the section Context-Nodes: Properties.

Recursion Nodes

Dynamic node nesting is possible within a context, creating what is called a recursion node. The node that is used for recursion is always a predecessor of the new node. The newly created recursion node is a reference to a predecessor node and therefore cannot be processed separately. Instead it takes on the structure of the node to be repeated.

The root node of a context cannot be used for a recursion.