ERA

Download the full-sized PDF of Queries and Query Processing in Object-Oriented Database SystemsDownload the full-sized PDF

Analytics

Share

Permanent link (DOI): https://doi.org/10.7939/R3ST89

Download

Export to: EndNote  |  Zotero  |  Mendeley

Communities

This file is in the following communities:

Computing Science, Department of

Collections

This file is in the following collections:

Technical Reports (Computing Science)

Queries and Query Processing in Object-Oriented Database Systems Open Access

Descriptions

Author or creator
Straube, Dave D.
Additional contributors
Subject/Keyword
Database Systems
Type of item
Report
Language
English
Place
Time
Description
Technical report TR90-33. Object-oriented database systems have been proposed as an effective solution for providing the data management facilities of complex applications. Proving the veracity of this claim and the investigation of related issues such as query processing have been hampered by the absence of a formal object-oriented data and query model. This thesis presents a model of queries for object-oriented databases and uses it to develop a query processing methodology. Two formal query languages are developed: a declarative object calculus and a procedural object algebra. The query processing methodology assumes that queries are initially specified as object calculus expressions. Algorithms are developed to prove the safety of calculus expressions and to translate them to their object algebra equivalents. Object algebra expressions represent sets of objects which may not all be of the same type. This can cause type violations when the expressions are nested. A set of type inference rules is presented which determines the type consistency of algebra expressions. The next step of the query processing methodology is logical optimization. Algebra expressions are optimized by applying equivalence preserving rewrite rules. Both algebraic and semantic rewrite rules are developed. Applicability conditions for algebraic rules are determined by pattern matching of query subexpressions while semantic rules additionally require that various conditions on the database schema be met. Thus the semantic rewrite rules are unique to a specific application. The final step in query processing is generation of access plans. The interface to an object manager subsystem which performs primitive operations on streams of objects is defined. Join enumeration algorithms from the relational model are adapted and extended to translate algebra expressions into access plans which are sequences of object manager operations.
Date created
1990
DOI
doi:10.7939/R3ST89
License information
Creative Commons Attribution 3.0 Unported
Rights

Citation for previous publication

Source
Link to related item

File Details

Date Uploaded
Date Modified
2014-04-28T21:36:47.712+00:00
Audit Status
Audits have not yet been run on this file.
Characterization
File format: pdf (Portable Document Format)
Mime type: application/pdf
File size: 2664300
Last modified: 2015:10:12 13:26:44-06:00
Filename: TR90-33.pdf
Original checksum: 8bdcf1c4c1b7bec9447a29fa5a60a422
Well formed: true
Valid: true
Page count: 128
Activity of users you follow
User Activity Date