Relationships are directed connections between two entities. Each relationship connects a parent entity and a child entity. BMC TrueSight Capacity Optimization uses relationships for three purposes:
Relationships can be made between any two entities in BMC TrueSight Capacity Optimization, subject to these rules:
The console workspace tree shows all of the visible relationships that are currently valid. If an entity is a child of two different entities, then the child is shown twice in the tree, once under each of its parents.
Relationships in BMC TrueSight Capacity Optimization are represented in a manner similar to configuration metric instances, except that relationships are not about an entity, but about two entities at once.
Mathematically, a relationship instance of one type is defined between any two entities, during any time period in which both entities are known to BMC TrueSight Capacity Optimization (that is, not dismissed). The instance may either be valid throughout that period, or not valid for any instant during that period, or valid for some sub-periods and invalid for the others. This is analogous to how configuration metric instances are valid or invalid through the life of an entity; see Metrics in BMC TrueSight Capacity Optimization.
To represent these relationship instances, the BMC TrueSight Capacity Optimization database contains for each instance a series of variable-length, non-overlapping validity periods, each representing a time period during which the relationship is valid. Because the validity periods in the series are non-overlapping, therefore at any given instant in time, the relationship instance is either valid or not, never both.
A BMC TrueSight Capacity Optimization database may contain thousands of entities that are alive (not dismissed) at the same time. Theoretically, there is an instance of a relationship of each type between each pair of these entities. But because most entities are related to only a few others in practice, most of these relationship instances are not valid at any time, and do not need to be explicitly represented in the BMC TrueSight Capacity Optimization database. The database stores only those relationships that are valid at least during a single period.
The definition of relationships has a schema that appears as a set of additional columns in the Dataset 59 (OBJREL). The most important aspects of relationships are:
A unique relationship type, which will distinguish this relationship from any other relationships between the same parent and child entity. If not specified, the type defaults to CONTAINS. See full list of types in Entity types.
ENTCATNM, DS_ENTNM, ENTCATNMPARENT, DS_ENTNMPARENT
This relationship is between these two entities.
This relationship is valid from timestamp FROMTS to timestamp TOTS. There may be multiple records for the same relationship for additional validity periods. For any time period that falls outside these validity periods, this relationship is invalid.
Sub-type of the child entity.
Whether this relationship is to be made visible in the console workspace tree, or not.
Of the above aspects of a relationship, the first two (Type and Entity pair) uniquely identify the relationship instance. The other aspects add information about the instance.
The various manual and automated operations on hierarchies described in Hierarchies seem simple. But the hierarchies visible in the console workspace tree represent only the current snapshot of the relationship graph in BMC TrueSight Capacity Optimization. The relationship instances recorded in BMC TrueSight Capacity Optimization represent parent-child connections over the entire time period from the creation of both entities to "infinity", an indeterminate future date.
For example, what seems like a move of an entity from one domain to another, as described in Adding systems and business drivers, is in fact a combination of two modifications:
Thus, as long as both parent and child entities remain alive in BMC TrueSight Capacity Optimization, it is possible to find out whether their parent-child relationship was valid or invalid at any time in the past.
When either or both of the entities is dismissed, however, the validity records of their relationships are automatically discarded.