Tài liệu Managing time in relational databases- P24 pptx
Tài liệu Managing time in relational databases- P24 pptx
... type of time within which points in time and/or periods of time are
ordered.
Components: type, point in time, time period.
temporal entity integrity
Mechanics: (i) for episodes, the constraint that ... 308–309
Pipelines
concept of, 268
data, 269
inflow, 268
lost data and, 295–296
outflow, 268
PK. See Primary key
Point in time, queries, 382–383
to Period of time, 333–341
to Po...
Tài liệu Managing time in relational databases- P2 pptx
... Versioning
Asserted Versioning Framework (AVF)
xxii
PREFACE
row the query author is interested in, two of those components
being time periods that may or may not intersect in various
ways. Continuing ... management losing
faith in data warehouse projects. As these large projects fell
increasingly behind schedule and rose increasingly over budget—
something large projects tend to do—the...
Tài liệu Managing time in relational databases- P4 pptx
... lacking a standard for the PERIOD datatype, we
will continue the practice of defining periods of time in terms of their begin and end
points in time.
Chapter 3 THE ORIGINS OF ASSERTED VERSIONING: ... record of when business events happen in the real
world. In addition, for most business purposes, we assume that a
SQL timestamp plus a defined interval of time will result in a
s...
Tài liệu Managing time in relational databases- P5 pptx
... [aligns] with the time period,
then it either [starts] the time period or [finishes] it. Otherwise,
the point in time occurs [during] the time period. If the point
in time [
excludes] the time period, ... clock ticks. This
point in time may either [
intersect] or [exclude] the time period.
If the point in time [
intersects] the time period, it also [fills] and
[
oc...
Tài liệu Managing time in relational databases- P6 pptx
... point in time
1
All effective time relationships exist within shared assertion time. Because this is so
important to keep in mind, we will often add the qualifier “within shared assertion
time ... effective -time contiguous
series of rows, starting with a row representing that object in the
time period T
10
–T
11
and continuing with rows representing
the object in time peri...
Tài liệu Managing time in relational databases- P8 pptx
... assertion time and
effective time is that two or more effective -time [
intersecting]
versions of the same object, in shared assertion time, would vio-
late temporal entity integrity, making conflicting ... within
shared assertion time, even a single effective -time clock tick
included in another version of that object already in the table.
Most physical transactions against bi-...
Tài liệu Managing time in relational databases- P15 pptx
... asserted, what information does
it contain that would justify retaining it in the database? Well, in
fact, a row in empty assertion time is informative. The informa-
tion it contains is information ... along the inflow pipelines whose termination
points are production tables, or along the outflow pipelines
whose points of origin are those same tables. The points of ori-
gin of inflow...
Tài liệu Managing time in relational databases- P1 ppt
... data in which none of that is
necessary, a world in which all pipeline datasets are contained
in the single table that is their destination or their point of origin.
In this world, maintaining ... useful by integrating them into
larger patterns. But he has worked in the world of business IT for
his entire career. And in that world, theory is fine, but it must
xx
PREFACE
MANAGING...
Tài liệu Managing time in relational databases- P3 doc
... point
in time forward to the point in time we are interested in.
But the defining feature of reconstructable methods is not the
movement of data from off-line to on-line storage. The defining ... waiting for the data, and the decisions
delayed until the data becomes available. In an increasingly
fast-paced business world, the opportunity cost of delays in
accessing data is incre...
Tài liệu Managing time in relational databases- P7 pdf
... effective time than assertion
time, we also present an in- line notation for single asserted
Managing Time in Relational Databases. Doi: 10.1016/B978-0-12-375041-9.00006-6
Copyright
#
2010 Elsevier Inc. ... integrity constraints in relational theory are entity
integrity, referential integrity and domain integrity. Entity integ-
rity insures that the object represented by a row...