Databases Reference
In-Depth Information
temporal extent state transformation taxonomy, {split}
Mechanics:
the temporal extent state transformation that removes the
representation of an object from one or more contiguous clock ticks that
were neither the earliest nor the latest clock ticks of an episode of that object
already present in the table.
Semantics:
the temporal extent state transformation that transforms one episode
into two adjacent episodes of the same object.
Components:
clock tick, contiguous, episode, object, representation, temporally
adjacent.
temporal foreign key
Mechanics:
a non-primary key column of an asserted version table which
contains the unique identifier of the object on which the object
represented by each of its own rows in an asserted version table is existence
dependent.
Semantics:
a column which designates an object on which the object represented
by the row which contains it is existence dependent.
Comments:
At the schema level, a temporal foreign key points from one table to a table
it is dependent on. But at the row level, it points from one row, which is a
version, to a group of one or more rows which make up an episode of the
object whose
oid
matches the oid value in that temporal foreign key.
At the instance level, temporal referential integrity guarantees that, for every
temporal foreign key, there is an episode of the designated object in the
referenced table, and that the effective time period of that episode in the
referenced table includes ([
fills
1
]) the effective time period of the version
which contains the referring temporal foreign key. (From Chapter 6.)
Temporal foreign keys, like conventional foreign keys, are the managed
object construct which represents the existence dependency of a child object
on a parent object.
Components:
asserted version table, existence dependency, object, object
identifier, represent.
temporal gap
Mechanics:
the existence of at least one unoccupied effective-time clock tick
between two time periods for the same object.
Components:
clock tick, effective time, object, occupy, time period.
temporal gap versioning
Mechanics:
a form of versioning similar to logical delete versioning, but in which
both a version begin date and a version end date are used to delimit the time
period of the version.
Semantics:
a form of versioning in which versions of the same object may or may
not be contiguous, and in which no version is physically deleted.
Comments:
Temporal gap versioning is not part of Asserted Versioning. See Chapter 4.
See also:
basic versioning, logical delete versioning, effective time
versioning
.
Components:
contiguous, logical delete versioning, object, time period, version,
version begin date, version end date.
temporal insert
Mechanics:
a temporal transaction against an asserted version table which creates
a single-row episode of the object specified in the transaction.
