Tài liệu Managing time in relational databases- P2 pptx
Tài liệu Managing time in relational databases- P2 pptx
... 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 pressure increased
to ... concepts.
Managing Time in Relational Databases. Doi: 10.1016/B978-0-12-375041-9.00001-7
Copyright
#
2010 Elsevier Inc. All rights of reproduction in any form reserved.
11...
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
... whether a point
in time is or is not contained in a period of time. Where P and T
are, respectively, a point in time and a period of time, and T
1
and
T
2
are dates delimiting T using the closed-open ... [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...
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 ... Versioning
In this variation on versioning, a logical delete flag is included
in the version table. It has two values, one marking the row as
not being a delete, and the other marking...
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 ... repre-
sentation of a timeline and a snapshot of effective time periods,
grouped by common assertion times along that timeline. With
the in- line notation, that context, too, is...
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- P24 pptx
... 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 Point in time, 341–342
Point in ... in time 1
[before] Period 1, 338–339,
339f
[before] Period 1, inverse of
relationship, 338–339
[before] Point in time 2, 341,
342f
[before] Point in time 2,
inverse...
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 ... systems used in education,
finance, health care, insurance, manufacturing, retailing and
transportation—all industries in which the authors have had
consulting experience.
In using the...
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 ... any
point in time between the starting balance and the current bal-
ance by going back to the starting balance and applying trans-
actions, in chronological sequence, up to the desire...
Tài liệu Managing time in relational databases- P7 pdf
... truth.
Temporal Integrity Constraints
The three integrity constraints in relational theory are entity
integrity, referential integrity and domain integrity. Entity integ-
rity insures that the ... 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...