Enhanced Strategy - Improvements over basic strategy

The basic versioning (generational) strategy works extremely well in all respects for object relationships considered as Type 1.

High performance builds without lookups.
High performance resolution of object relationships during target audience queries.
High fidelity replication of keys.
Complete referential integrity.
Simple exception reporting.
Simple dimensional object maintenance.
Retention of history

However this is not all true for object relationships considered to be of Type 2 or of a temporal nature.

An extension of the model could be considered.

Use of the epoch as a generation has some advantages with regard to temporal dimension objects and very late arriving referential data that would split an existing generation rather than simply being the latest.

Taking the dimensional object

Account no	Address	Startpoint	DHkey	Generation
1	1 Acacia Avenue	01/01/2000	c4ca4238a0b923820dcc509a6f75849b	1
1	101 High Street	02/02/2010	c4ca4238a0b923820dcc509a6f75849b	2
1	52 Festive Road	30/04/2011	c4ca4238a0b923820dcc509a6f75849b	3
2	7 Block Lane	01/01/2000	c81e728d9d4c2f636f067f89cc14862c	1
3	DUMMY	02/03/2010	eccbc87e4b5ce2fe28308fd9f2a7baf3	0
3	10 Upping Street	01/03/2010	eccbc87e4b5ce2fe28308fd9f2a7baf3	1

Using epoch as generation

Account no	Address	Startpoint	DHkey	Generation
1	1 Acacia Avenue	01/01/2000	c4ca4238a0b923820dcc509a6f75849b	946684800
1	101 High Street	02/02/2010	c4ca4238a0b923820dcc509a6f75849b	1265068800
1	52 Festive Road	30/04/2011	c4ca4238a0b923820dcc509a6f75849b	1301785200
2	7 Block Lane	01/01/2000	c81e728d9d4c2f636f067f89cc14862c	946684800
3	DUMMY	02/03/2010	eccbc87e4b5ce2fe28308fd9f2a7baf3	0
3	10 Upping Street	01/03/2010	eccbc87e4b5ce2fe28308fd9f2a7baf3	1267401600

Note that Dummies are still identifiable by generation 0

Lets say we receive a reference to account 1 changing address on 01/11/2010 for some reason we failed to receive this reference at the time so have to handle it retrospectively.

Account no	Address	Startpoint	DHkey	Generation
1	1 Acacia Avenue	01/01/2000	c4ca4238a0b923820dcc509a6f75849b	946684800
1	101 High Street	02/02/2010	c4ca4238a0b923820dcc509a6f75849b	1265068800
1	52 Festive Road	30/04/2011	c4ca4238a0b923820dcc509a6f75849b	1301785200
1	62 West Wallaby Street	01/11/2010	c4ca4238a0b923820dcc509a6f75849b	1288569600

The epoch as a generation has the advantage of the reference instance being inserted in the correct generation order of change.

An additional consideration of this strategy is that the epoch granularity can be reduced dependent on the temporal granularity of the dimensional object so for instance if the granularity is day (date) then simply dividing the epoch by 86400

e.g. 1288569600 becomes 14914

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