Browsing by Subject "relational model"

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Access status: Open Access ,
Język UML 2.0 w modelowaniu relacyjnych baz danych
(Wydawnictwa AGH, 2006) Skrzyński, Paweł
UML has been accepted as the standard modelling language for specifying software and system architectures. Second version of language, known as UML version 2.0, addressed most of the problems that architects faced while modelling software with previous version of this language and confirmed its position as the most popular modelling language used in object-oriented approaches to software development. On the other hand relational model of storing data today is the most popular model and the most common methodology of modelling data in relational systems is classic Entity-Relationship model and its extensions. Although UML was strongly influenced by these mechanisms, in author's opinion, it provides much more expressive modelling power. From the static point of view of the system transformation between ERD diagrams and relational tables is relatively ease, so transformation rules between class diagrams and relational tables have been widely discussed in literature [5, 3]. In this paper some additional transformations which are possible from class diagrams and activity diagrams to relational tables, stored procedures and functions are discussed.
Access status: Open Access ,
Realization of a system of efficient querying of hierarchical data transformed into a quasi-relational model
(Wydawnictwa AGH, 2016) Furmanek, Adam; Tokaj, Jakub; Marcjan, Robert; Siwik, Leszek
Extensible Markup Language was mainly designed to easily represent documents, however, it has evolved and is now widely used for the representation of arbitrary data structures. There are many Application Programming Interfaces (APIs) to aid software developers with processing XML data. There are also many languages for querying and transforming XML, such as XPath or XQuery, which are widely used in this field. However, because of the great flexibility of XML documents, there are no unified data storing and processing standards, tools, or systems. On the other hand, a relational model is still the most-commonly and widely used standard for storing and querying data. Many Database Management Systems consist of components for loading and transforming hierarchical data. DB2 pureXML or Oracle SQLX are some of the most-recognized examples. Unfortunately, all of them require knowledge of additional tools, standards, and languages dedicated to accessing hierarchical data (for example, XPath or XQuery). Transforming XML documents into a (quasi)relational model and then querying (transformed) documents with SQL or SQL–like queries would significantly simplify the development of data-oriented systems and applications. In this paper, an implementation of the SQLxD query system is proposed. The XML documents are converted into a quasi-relational model (preserving their hierarchical structure), and the SQL–like language based on SQL-92 allows for efficient data querying.