Databases Reference
In-Depth Information
9
AN INTRODUCTION TO
TEMPORAL TRANSACTIONS
CONTENTS
Effective Time Within Assertion Time
192
Explicitly Temporal Transactions: The Mental Model
A Taxonomy of Temporal Extent State Transformations
197
The Asserted Versioning Temporal Transactions
The Temporal Insert Transaction
The Temporal Update Transaction
The Temporal Delete Transaction
Glossary References
Temporal transactions are inserts, updates or deletes whose
targets are asserted version tables. But temporal transactions
are not submitted directly to the DBMS. The work that has
to be done to manage conventional tables is straightforward
enough that we can let users directly manipulate those tables.
But bi-temporal tables, including asserted version tables, are too
complex to expose to the transaction author. The difference
between what the user wants done, and what has to take place
to accomplish it, is too great. And so temporal transactions
are the way that the query author tells us what she wants done
to the database, without having to tell us how to do it. The
mechanics of how her intentions are carried out are encapsulated
within our Asserted Versioning Framework. All that the appli-
cation accepting the transaction has to do is to pass it on to
the AVF.
A DBMS can enforce such constraints as entity integrity and
referential integrity, but it cannot enforce the significantly more
complex constraints of their temporal analogs. It is the AVF
which enforces temporal entity integrity and temporal refer-
ential
integrity.
It
is the AVF which rejects any temporal
