Databases Reference
In-Depth Information
Completing the Deferred Update to a Deferred
Assertion
The remaining analysis is straightforward. P861(r9) matches
the deferred update transaction. P861(r10) is of no interest to
the transaction because its effective time period does not share
even a single clock tick with the effective timespan of the
transaction.
Having created a target row which matches the transaction,
the AVF now updates that row with the new copay amount. Note
that it does not withdraw P861(r9) and supercede it with a new
row. It could do that, but there is no need to do so because we
are still in the midst of an atomic and isolated unit of work. At
this point, the change to the copay amount is recorded. At this
point, the update is complete. The result is shown in
Figure 12.6
.
As directed by the transaction, the AVF has created a version
of P861, for the effective time period of May 2012, that will not
be asserted until January 2090. The first deferred update
changed the copay amount for P861, for the month of May
2012, from $30 to $55. This second deferred update corrected
the copay amount which the first one set to $55. It changed it
to $50.
Once again, we retain the angle brackets in the illustration to
make it easy to identify the rows involved in the transaction. But
the transaction, at this point, is complete. All DBMS locks are
released, and all the rows in
Figure 12.6
are now visible in the
database. P861(r9 & r10) are not locked. P861(r8) has been
overridden by those next two rows, and moved into empty asser-
tion time. But note that P861(r6) is still both currently asserted
and locked.
Policy Table
copay
Row
#
1
oid
eff-beg
eff-end
asr-beg
asr-end
epis-
beg
clinet
type
row-crt
Mar12
9999
9999
P861
Nov11
Nov11
Nov11
C882
HMO
Nov11
Mar12
$20
$50
$30
$40
$30
$30
$30
$55
$55
$55
2
3
4
5
6
7
<8>
<9>
<10>
P861
P861
P861
P861
P861
P861
P861
P861
P861
Mar12
Apr12
Mar12
Nov11
Nov11
Nov11
Nov11
Nov11
Nov11
Nov11
Nov11
Nov11
C882
C882
C882
C882
C882
C882
C882
C882
C882
PPO
Apr12
Aug12
Apr12
Jan13
Apr12
Aug12
HMO
POS
Aug12
9999
Aug12
9999
9999
May12
Apr12
Jan13
Jan13
Jan13
Jan13
Jan13
Feb13
Feb13
HMO
HMO
HMO
HMO
HMO
HMO
May12
Jul12
Jan90
Jan13
Jul12
Aug12
9999
Jan13
Jan90
Jan90
Jan90
May12
May12
Jun12
Jul12
Jun12
Jul12
Jan90
9999
9999
Figure 12.6 Completing the Deferred Update.
