Motivated by Geographical Information Systems (GIS) applications, we introduce a new data model for mutually nested objects. Combining features from relational as well as object-oriented database systems, our data model is efficient for queries involving multiple access patterns. By maintaining symmetrical relationships between entities, we allow nesting to be formulated dynamically at the query level rather than the data model level, thus dissociating the data structure from the access method. In addition, we do not favor one access pattern over another by clustering data in one particular manner, giving therefore flexibility and performance to our system. / In order to integrate nesting into the relational algebra, we propose an extension to Relix, which is an academic database management system. We then show how those modifications can be used in a wide variety of queries, provide an algorithm to translate nested queries into flat relational expressions, and finally show that similar improvements can be applied to SQL allowing nested queries to be expressed more naturally.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.27401 |
| Date | January 1997 |
| Creators | Saliba, Walid. |
| Contributors | Merrett, Timothy H. (advisor) |
| Publisher | McGill University |
| 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 |
| Format | application/pdf |
| Coverage | Master of Science (School of Computer Science.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001572760, proquestno: MQ29776, Theses scanned by UMI/ProQuest. |
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