Databases Reference
In-Depth Information
Temporal Managed Objects and Temporal
Referential Integrity
Temporal referential integrity relates a child
version
to a par-
ent
episode
. It is important to understand why this is so, to
understand why TRI is not a relationship between episodes
and other episodes, or between versions and other versions.
Child Managed Objects
First of all, the child managed object in a TRI relationship
cannot be an episode. The reason is that within the same
episode, the owning parent object can change over time. For
example, as policy episodes P861-A and P861-C in
Figure 11.1
illustrate, different versions within the same episode can have
different temporal foreign keys (TFKs), which means that they
can designate different parent objects. Of course, since those
C903
Episode C903-A
Episode C903-B
Episode C903-C
1
2
3
4
5
6
Jan
2010
Jan
Jan
2012
Jan
2013
Jan
2014
2011
Episode C882-A
Episode C882-B
Episode C882-C
1
2
3
4
Jan
2010
Jan
2011
Jan
2012
Jan
2013
Jan
2014
P861
E
pisode P861-A
Episode P861-B
Episode P861-C
2
1
345 6
7
8
Jan
2010
Jan
2011
Jan
2012
Jan
2013
Jan
2014
Figure 11.1 Temporal Referential Integrity: The Basic Diagram.
