Databases Reference
In-Depth Information
Semantics:
a temporal transaction against an asserted version table which places
business data representing an object into an effective time period that is not
contiguous with any other clock ticks in which the same object is
represented.
Comments:
A temporal insert adds a representation of its specified object to a
series of one or more contiguous effective time clock ticks. In the
process, it may {create} an entire single-episode version, or {merge}
two adjacent episodes, or {lengthen} an episode either forwards or
backwards.
Components:
asserted version table, business data, clock tick, contiguous,
effective time period, episode, object, represent, temporal transaction,
temporally adjacent.
temporal parameter
Mechanics:
one of the three asserted versioning dates that can be specified on a
temporal transaction, those being the effective begin date, the effective end
date and the assertion begin date.
Semantics:
the means by which an assertion time period and an effective time
period are defined on a temporal transaction.
Components:
assertion begin date, assertion time period, effective begin date,
effective end date, temporal transaction.
temporal primary key
Mechanics:
the unique identifier of a row in an asserted version table, made up of
(i) an object identifier (oid), (ii) an effective begin date, and (iii) an assertion
begin date.
Semantics:
the unique identifier of a row in a bi-temporal table, made up of
(i) the unique identifier of a persistent object, (ii) a unique designation of an
effective time period, and (iii) a unique designation of an assertion time
period.
Components:
asserted version table, bi-temporal, effective begin date, effective
time period, assertion begin date, assertion time period, object identifier, oid,
persistent object.
temporal referential integrity
Mechanics:
the constraint that for every version which contains a temporal
foreign key, there is an episode of the object which that temporal foreign
key references such that, within shared assertion time, the effective time
period of that episode includes ([fills
1
]) the effective time period of that
version.
Semantics:
the constraint that, in any clock tick of assertion time, every clock tick
that is occupied by a representation of a child object is also occupied by one
representation of each of its parent objects.
Comments:
A temporal referential integrity relationship between a child managed
object and a parent managed object is based on an existence dependency
between the objects which those managed objects represent. (From
Chapter 11.)
Components:
Allen relationship [fills
1
], asserted version table, assertion
time, child object, clock tick, effective time period, episode, include,
object, occupy, parent object, reference, shared assertion time, temporal
foreign key.
