First-Order Queries on Databases Embedded in an Infinite Structure
نویسندگان
چکیده
We consider generic isomorphism invariant queries on rela tional databases embedded in an in nite background structure As sume a generic query is expressible by a rst order formula over the embedded domain that may involve both the relations of the database and the relations and functions of the background structure Then this query is already expressible by a rst order formula involving just an auxiliary linear ordering as background structure We present an elementary proof of this fact
منابع مشابه
An Ehrenfeucht-Fraïssé Approach to Collapse Results for First-Order Queries over Embedded Databases
We present a new proof technique for collapse results for first–order queries on databases which are embedded in N or R>0. Our proofs are by means of an explicitly constructed winning strategy for Duplicator in an Ehrenfeucht–Fräıssé game, and can deal with certain infinite databases where previous, highly involved methods fail. Our main result is that first–order logic has the natural–generic ...
متن کاملارائه روشی پویا جهت پاسخ به پرسوجوهای پیوسته تجمّعی اقتضایی
Data Streams are infinite, fast, time-stamp data elements which are received explosively. Generally, these elements need to be processed in an online, real-time way. So, algorithms to process data streams and answer queries on these streams are mostly one-pass. The execution of such algorithms has some challenges such as memory limitation, scheduling, and accuracy of answers. They will be more ...
متن کاملEmbedded Finite Models, Stability Theory and the Impact of Order
We extend bounds on the expressive power of firstorder logic over finite structures and over ordered finite structures, by generalizing to the situation where the finite structures are embedded in an infinite structure M , where M satisfies some simple combinatorial properties studied in model-theoretic stability theory. We first consider first-order logic over finite structures embedded in a s...
متن کاملA Method for Protecting Access Pattern in Outsourced Data
Protecting the information access pattern, which means preventing the disclosure of data and structural details of databases, is very important in working with data, especially in the cases of outsourced databases and databases with Internet access. The protection of the information access pattern indicates that mere data confidentiality is not sufficient and the privacy of queries and accesses...
متن کاملThe Natural Order-Generic Collapse for omega-Representable Databases over the Rational and the Real Ordered Group
We consider order-generic queries, i.e., queries which commute with every order-preserving automorphism of a structure’s universe. It is well-known that first-order logic has the natural order-generic collapse over the rational and the real ordered group for the class of dense order constraint databases (also known as finitely representable databases). I.e., on this class of databases over 〈Q, ...
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:
- Inf. Process. Lett.
دوره 60 شماره
صفحات -
تاریخ انتشار 1996