An Algorithm for Handling Many Relational Calculus Queries Efficiently
نویسنده
چکیده
This article classifies a group of complicated relational calculus queries whose search algorithms run in time O(I LogI + U) and space O(I) , where I and U are the sizes of the input and output, and d is a constant depending on the query (which is usually, but not always, equal to zero or one). Our algorithm will not entail any preprocessing of the data.
منابع مشابه
Relational Databases Query Optimization using Hybrid Evolutionary Algorithm
Optimizing the database queries is one of hard research problems. Exhaustive search techniques like dynamic programming is suitable for queries with a few relations, but by increasing the number of relations in query, much use of memory and processing is needed, and the use of these methods is not suitable, so we have to use random and evolutionary methods. The use of evolutionary methods, beca...
متن کاملExtending the Qualitative Trajectory Calculus Based on the Concept of Accessibility of Moving Objects in the Paths
Qualitative spatial representation and reasoning are among the important capabilities in intelligent geospatial information system development. Although a large contribution to the study of moving objects has been attributed to the quantitative use and analysis of data, such calculations are ineffective when there is little inaccurate data on position and geometry or when explicitly explaining ...
متن کاملIndexing and Querying Semistructured Data Views of Relational Database
The most promising and dominant data format for data processing and representing on the Internet is the Semistructured data form termed XML. XML data has no fixed schema; it evolved and is self describing which results in management difficulties compared to, for example relational data. XML queries differ from relational queries in that the former are expressed as path expressions. The efficien...
متن کاملبهبود الگوریتم انتخاب دید در پایگاه داده تحلیلی با استفاده از یافتن پرس وجوهای پرتکرار
A data warehouse is a source for storing historical data to support decision making. Usually analytic queries take much time. To solve response time problem it should be materialized some views to answer all queries in minimum response time. There are many solutions for view selection problems. The most appropriate solution for view selection is materializing frequent queries. Previously posed ...
متن کاملThe Dichotomous Intensional Expressive Power of the Nested Relational Calculus with Powerset
Most existing studies on the expressive power of query languages have focused on what queries can be expressed and what queries cannot be expressed in a query language. They do not tell us much about whether a query can be implemented efficiently in a query language. Yet, paradoxically, efficiency is of primary concern in computer science. In this paper, the efficiency of queries in NRC(powerse...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- J. Comput. Syst. Sci.
دوره 65 شماره
صفحات -
تاریخ انتشار 2002