Hierarchy Nodes
Hierarchy nodes are components of a characteristic hierarchy. A characteristic hierarchy is assigned to a hierarchy basic characteristic and is therefore subject to the valid hierarchy properties Version Dependency, Time Dependency, Interval, and Sign Reversal for all hierarchies assigned to this characteristic (see Hierarchy Properties).
The structure of a characteristic hierarchy is defined by the link relationships among the hierarchy nodes.
Each node has exactly one parent node (predecessor). The "depth" (level) of the node corresponds to the number of its predecessors increasing up to the root of one. This means that the roots have level 1.
The set quantity of children or subnodes (successors) is assigned to each node. The "degree" of a node corresponds to the number of its successors.
Nodes that have special features in one of the two relationships are roots (nodes) and leaves. All nodes are indicated as inner nodes whose degree is not zero, meaning that they have successors.
With regard to the structure of a hierarchy, the hierarchy nodes are assembled into hierarchy levels and subtrees.
Depending on whether a node refers to a hierarchy basic characteristic or not, we differentiate postable and not postable nodes.
All nodes (except for leaves and link nodes) can only occur once in a hierarchy. More information: Modeling Nodes and Leaves and Link Nodes.
Special hierarchy nodes
Hierarchy nodes |
Description |
|---|---|
Root (nodes) |
A node that is not assigned under any node and has no parent node (predecessor). A hierarchy can have more than one root node. |
Leaf |
A node without lower-level nodes (successors). Leaves are postable but are not postable nodes (see the "Postability of Nodes" table below). Leaves are always characteristic values for the hierarchy basic characteristic. Value specification: The value is moved from the InfoProvider. |
Intervals |
A quantity of leaves that are indicated by their lower and upper limit. |
Inner nodes |
A node that has successors, which means all nodes except for leaves. |
Grouping of hierarchy nodes
Grouping |
Description |
|---|---|
Hierarchy level |
A hierarchy level consists of all nodes with the same depth. Root nodes have depth (level) 1. The depth of a node corresponds to the number of parent or grandparent nodes up to the root node + 1 (increased by one) A hierarchy can have a maximum of 98 levels. Each level can have a name. |
Subtree |
A subtree includes a node (root node of the subtree) with its lower-level or subnodes. Nodes that are on the lower border of a subtree are called border nodes. This is relevant for hierarchy authorizations (see Settings for Hierarchy Authorizations). |
Postability of nodes
Postability |
Description |
|---|---|
Postable nodes |
A node that corresponds to a characteristic value for the hierarchy basic characteristic. (In other words, a node that corresponds to a characteristic value for a characteristic that references the hierarchy basic characteristic. This definition includes the hierarchy basic characteristic.) Unlike a leaf, additional nodes or leaves are assigned under a postable (inner) node. Value specification: The value of a postable node is specified by the aggregation of the values of its lower-level nodes and of its value in the InfoProvider. For an example, see Modeling Nodes and Leaves. |
Non-postable nodes |
A node that does not refer to a hierarchy basic characteristic and is not a postable node (see Text Nodes, External Characteristic Nodes). Value specification: The value of a node that is not postable is specified by the aggregation of the values of its child nodes. |
Text node |
A text node is a new, artificial term. Text nodes are special characteristic nodes for the artificial characteristic 0HIER_NODE. |
External characteristic nodes |
A node that is identified by any specification of any InfoObject is an External Characteristic Node. For a characteristic to be used in the hierarchy as an external characteristic node, this has to be explicitly selected in the InfoObject maintenance for the hierarchy basic characteristic. |
Not assigned |
The system automatically creates a root node REST_H, under which all characteristic values are positioned. These characteristic values exist in the master data, but are not explicitly arranged in the hierarchy. The Not Assigned node guarantees that no data is lost when a presentation hierarchy is activated (see Characteristic Properties). In the query, this node is always collapsed first and does not react to Expand to Level It can be explicitly expanded however. |
Hierarchy balance
Hierarchy type |
Description |
|---|---|
Unbalanced |
A hierarchy whose leaves are on various levels is called an unbalanced hierarchy. If various sources of information are delivered with different degrees of detail (one to the Material level for example, another only to the Material Group level), this can result in unbalanced hierarchies (see the example below). |
Balanced |
A hierarchy whose leaves all have the same depth is called a balanced hierarchy. A balanced hierarchy, in which all nodes for a level have the same semantics (such as characteristic nodes with the same characteristic), is called a Named Level Hierarchy (see example 1 below). In level maintenance, you can assign the levels for the respective texts (see Level Maintenance). Typical examples of these hierarchies are geographic hierarchies, with the levels Continent- Country- State- Region- City for example, or time hierarchies (see the example below). |
SAP NetWeaver Business Intelligence can process both balanced and unbalanced hierarchies without restriction.
Example 1
The following graphic provided an example of a hierarchy for InfoObject Month 0CALMONTH to illustrate the relationships between the hierarchy nodes and their grouping in hierarchy levels.
This time hierarchy is a typical example of a balanced hierarchy. It has several root nodes, as the nodes with characteristic values 2002 and 2003 for the InfoObjects transferred in addition to the time characteristic Year 0CALYEAR ( external characteristic node), are not normally positioned under a special parent node (like text node Year).
The hierarchy has three levels. Since each level corresponds to an InfoObject (0CALYEAR, 0CALQUARTER, 0CALMONTH), this is a Named Level Hierarchy.
Postable nodes are green, while nodes that cannot be posted to are displayed in yellow. The definition of nodes 1.2002/0CALQUARTER and 1.2003/0CALQUARTER is identical. Specifiying intervals as a summary of several leaves provides an easier entry option, but is not a new structure component.
Example 2a
The following graphic provides an example of a hierarchy for InfoObject Customer to illustrate the relationships between the hierarchy nodes and their grouping in hierarchy levels. This customer hierarchy is a typical example of an unbalanced hierarchy and has one root node only. Postable nodes and leaves are green, while nodes that cannot be posted to are displayed in yellow.
Example 2b
The following graphic provides an example of a hierarchy for the InfoObject Customer to illustrate how this kind of hierarchy is displayed when you model it in the hierarchy maintenance transaction. The various node types are displayed as follows:
Folder symbol: Text nodes, in this case the Customer Hierarchy root node
Yellow InfoObject symbol: Nodes that cannot be posted with characteristic values for the additionally transferred InfoObjects Region ( External Characteristic Nodes) in the customer hierarchy
Green InfoObject symbol: Postable nodes and leaves for InfoObject Customer
See also: