A database schema should consist of structures and semantic integrity constraints. Se
mantic integrity constraints (SICs) are invariant restrictions on the static states of the
stored data and the state transitions caused by the primitive operations: insertion, dele
tion, or update. Traditionally, database design has been carried out on an ad hoc basis
and focuses on structure and efficiency. Although the E-R model is the popular concep
tual modelling tool, it contains few inherent SICs. Also, although the relational database
model is the popular logical data model, a relational database in fourth or fifth normal
form may still represent little of the data semantics. Most integrity checking is distributed
to the application programs or transactions. This approach to enforcing integrity via the
application software causes a number of problems.
Recently, a number of systems have been developed for assisting the database design
process. However, only a few of those systems try to help a database designer incorporate
SICs in a database schema. Furthermore, current SIC representation languages in the
literature cannot be used to represent precisely the necessary features for specifying
declarative and operational semantics of a SIC, and no modelling tool is available to
incorporate SICs.
This research solves the above problems by presenting two models and one subsystem.
The E-R-SIC model is a comprehensive modelling tool for helping a database designer in
corporate SICs in a database schema. It is application domain-independent and suitable
for implementation as part of an automated database design system. The SIC Repre
sentation model is used to represent precisely these SICs. The SIC elicitation subsystem
would verify these general SICs to a certain extent, decompose them into sub-SICs if
necessary, and transform them into corresponding ones in the relational model.
A database designer using these two modelling tools can describe more data semantics
than with the widely used relational model. The proposed SIC elicitation subsystem can
provide more modelling assistance for him (her) than current automated database design
systems.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:BVAU.2429/3147 |
| Date | 11 1900 |
| Creators | Yang, Heng-li |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Relation | UBC Retrospective Theses Digitization Project [http://www.library.ubc.ca/archives/retro_theses/] |
Page generated in 0.0024 seconds