THE ORIGINS OF ASSERTED VERSIONING: IT BEST PRACTICES - Managing Time in Relational Databases - page 71

4

THE ORIGINS OF ASSERTED
VERSIONING: IT BEST
PRACTICES

CONTENTS
A Non-Temporal Table and a Basic Version Table 77

Basic Versioning 79
An Insert Transaction 79
An Update Transaction 80
A Second Update Transaction

81

A Delete Transaction 82
Logical Delete Versioning 83
Temporal Gap Versioning 86
Effective Time Versioning 87
Effective Time Versioning and Retroactive Updates 89
Effective Time Versioning and Retroactive Inserts and Deletions

90

The Scope and Limits of Best Practice Versioning 92

Glossary References 93

Lots of things are important to us. That's why we keep data
about them in our databases. In a non-temporal table, each one
of them, i.e. each object, is represented by one and only one
row. In a version table, however, each row represents a period of
time in the life of an object, and is a description of what that
object is like during that time. And so, in a version table, there
can be any number of rows representing the same object, each
describing what the object is like during a different period of time.
In an assertion table, on the other hand, each row represents
an assertion about an object, and represents what we said, dur-
ing a specific period of time, that object is like. And so, in an
assertion table, there also can be any number of rows
representing the same object, each describing what we said, at
a different period of time, the object is like.