tailieunhanh - Database Modelling in UML

The new information incorporated into the database also resulted in virtually no changes in the reasons for the restatements that we originally reported (see table 1, enclosure I). The most notable changes involved restatements that we had originally classified as Additional information allowed us to reclassify numerous restatements from the ìotherî category. As a result, the ìcost or expenseî and ìrestructuring, assets, or inventoryî categories, which had originally included percent and percent of the 919 restatements, respectively, rose to percent and percent. Further, with the new information, the share of restatements classified in the ìrevenue recognitionî category fell slightly, from. | Database Modelling in UML By Geoffrey Sparks sparks@ http Originally published in Methods Tools e-newsletter http mt Introduction When it comes to providing reliable flexible and efficient object persistence for software systems today s designers and architects are faced with many choices. From the technological perspective the choice is usually between pure Object-Oriented Object-Relational hybrids pure Relational and custom solutions based on open or proprietary file formats eg. XML OLE structured storage . From the vendor aspect Oracle IBM Microsoft POET and others offer similar but often-incompatible solutions. This article is about only one of those choices that is the layering of an object-oriented class model on top of a purely relational database. This is not to imply this is the only best or simplest solution but pragmatically it is one of the most common and one that has the potential for the most misuse. We will begin with a quick tour of the two design domains we are trying to bridge firstly the object-oriented class model as represented in the UML and secondly the relational database model. For each domain we look only at the main features that will affect our task. We will then look at the techniques and issues involved in mapping from the class model to the database model including object persistence object behaviour relationships between objects and object identity. We will conclude with a review of the UML Data Profile as proposed by Rational Software . Some familiarity with object-oriented design UML and relational database modelling is assumed. The Class Model The Class Model in the UML is the main artefact produced to represent the logical structure of a software system. It captures the both the data requirements and the behaviour of objects within the model domain. The techniques for discovering and elaborating that model are outside the scope of this article so we will .