Databases Reference
In-Depth Information
reliable business key
Mechanics:
a business key which can be used to match data on a temporal
transaction to one or more rows in the target table for that transaction.
Semantics:
a business key which represents one and only one object.
Components:
business key, object, represent, target table, temporal transaction.
replace
Mechanics:
a row X replaces a row Y if and only if X and Y both represent the
same object, X's effective time period [
equals
] Y's effective time period, X's
business data is identical to Y's business data, and X's assertion time period
[finishes] Y's assertion time period.
Semantics:
a row X replaces a row Y if and only if X and Y both represent the same
object, and X is a business-data identical assertion about what Y is like during
the effective time period specified by Y.
Comments:
See also:
withdraw, supercede
.
A row X replaces a row Y if and only if X says the same thing about what
the object Y represents is like, during the effective time period specified by Y.
If a superceding version was also created as part of the temporal update
transaction which created a replacement version, then this replacement
version will [meet] that superceding version in effective time, while
having an [
equal
] assertion time.
A temporal update transaction whose effective time period [
intersects
]
that of a target version, but does not [
equal
] it, requires the AVF to
withdraw the target version and then to split that target version into one
version that matches the transaction, and one (or two) versions that do
not. This is done with the
f
CUT function. The resulting version or
versions that do not match the transaction are replacements, with
identical business data. The one version that does match the transaction
is updated with the new business data, and supercedes the corresponding
effective timespan of the withdrawn version.
Components:
version, assertion, effective time, match, withdraw, supercede, temporal.
represent
Mechanics:
a managed object represents an object in a series of one or more clock
ticks if and only if those clock ticks are all included within the time period of
that managed object.
Comments:
See also:
occupy
.
Components:
managed object, clock tick, object, time period.
re-present
Description:
we use the hyphenated form “re-present” advisedly. We do mean that
we will show how to
represent
those internalized datasets as queryable
objects, in the ordinary sense of the word “represent”. But we also wish to
emphasize that we are re-presenting, i.e. presenting again, things whose
presence we have removed.
2
Those things are the external pipeline datasets
2
We also wish to avoid confusion with our technical term
represent
, in which business
data, we say, is represented in an effective time clock tick within an assertion time
clock tick just in case that business data exists on an asserted version row whose
assertion and effective time periods contain those clock tick pairs.
