LIP6 2001/029
- Thesis
Contraintes d'intégrité et transactions imbriquées - C. P. Leon Luna
- 72 pages - 07/19/2001- document en - http://www.lip6.fr/lip6/reports/2001/lip6.2001.029.pdf - 521 Ko
- Contact : cleon (at) nullstrix.ciens.ucv.ve
- Ancien Thème : OASIS
- Keywords : nested transactions, integrity constraints, object oriented databases, distributed systems
- Publisher : Stephane.Gancarski (at) nulllip6.fr
Among the advanced transaction models, nested transactions are without doubt the most known and used. This model allows to decompose a transaction into a hierarchy of sub-transactions, which may be executed in parallel. This hierarchy can be of an arbitrary depth. This PhD thesis proposes solutions in the context of nested transactions. On one hand, we evaluate a system that supports nested transactions, in order to study the behavior of nested transactions in distributed systems. On the other hand, we propose a innovating method to maintain integrity constraint in databases that support nested transactions. The key idea of our solution for the checking of integrity,constraints with nested transactions, is to associate the control of each constraint with the smallest common ancestor (in the nested transaction tree) of all sub-transactions that touch the constraint. Our solution has been implemented in a nested transaction manager prototype which integrates the constraint checking with the execution control. The proposal is extended to multi-databases. We establish different checking strategies according to the constraint nature and to the transaction structure. The main advantage of our solution is that it doesn't interfer with the nested transaction execution control, which makes it flexible and portable. Transparency is provided : users don't have to write any control code, neither in the transactions nor in constraint definitions.