On database query languages for K-relations
نویسندگان
چکیده
Article history: Available online 22 September 2009
منابع مشابه
انتخاب مناسبترین زبان پرسوجو برای استفاده از فراپیوندها جهت استخراج دادهها در حالت دیتالوگ در سامانه پایگاه داده استنتاجی DES
Deductive Database systems are designed based on a logical data model. Data (as opposed to Relational Databases Management System (RDBMS) in which data stored in tables) are saved as facts in a Deductive Database system. Datalog Educational System (DES) is a Deductive Database system that Datalog mode is the default mode in this system. It can extract data to use outer joins with three query la...
متن کاملOn BP-complete query languages on K-relations
The relational model has recently been extended to so-called K-relations in which tuples are assigned a unique value in a semiring K. A query language, denoted by RA+K, similar to the classical positive relational algebra, allows for the querying of K-relations. We study the completeness of RA+K in the sense of Bancilhon and Paredaens (BP) and show that RA+K is, in general, not BP-complete. Fac...
متن کاملRelational 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 کاملDatabase Theory Column Victor Vianu Query Languages for Bags Expressive Power and Complexity 1
One of the characteristics of advanced database systems is that they must handle data which no longer ts the traditional relational style. The present column summarizes recent results on one such extension, where databases handle bags (multisets) rather than just sets. The results illustrate an important research direction in Database Theory. Abstract Most database theory focused on investigati...
متن کاملA Database Model for Medical Consultation
The database model presented in this paper is suitable for application in which queries may require non-crisp references to certain attributes. The data item (attribute) values may be crisp or fuzzy. For instance, such adjectives as 'high' or 'normal' may be attribute values for the attribute blood pressure. A disease or a condition can be described by a number of symptoms which may be crisp al...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- J. Applied Logic
دوره 8 شماره
صفحات -
تاریخ انتشار 2010