Database Db Research Articles

Detecting Metadata-Related Logic Bugs in Database Systems via Raw Database Construction

Database Management Systems (DBMSs) are widely used to efficiently store and retrieve data. DBMSs usually support various metadata, e.g., integrity constraints for ensuring data integrity and indexes for locating data. DBMSs can further utilize these metadata to optimize query evaluation. However, incorrect metadata-related optimizations can introduce metadata-related logic bugs, which can cause a DBMS to return an incorrect query result for a given query. In this paper, we propose a general and effective testing approach, Raw database construction (Radar), to detect metadata-related logic bugs in DBMSs. Given a database db containing some metadata, Radar first constructs a raw database rawDb , which wipes out the metadata in db and contains the same data as db. Since db and rawDb have the same data, they should return the same query result for a given query. Any inconsistency in their returned query results indicates a metadata-related logic bug. To effectively detect metadata-related logic bugs, we further propose a metadata-oriented testing optimization strategy to focus on testing previously unseen metadata, thus detecting more metadata-related logic bugs quickly. We implement and evaluate Radar on five widely-used DBMSs, and have detected 42 bugs, of which 38 have been confirmed as new bugs and 16 have been fixed by DBMS developers.

THE USE OF MARKOV ALGORITHMS FOR THE STUDY OF l-VOIDS IN BIG DATA OF SOCIO-ECONOMIC SYSTEMS. PART 2

The second part of the article is presented. Big data l-voids are considered using the N-scheme of the Markov algorithm. The diagrams of occurrences of l-voids in a semi-Eulerian cycle containing an Euler path, a matroid and an incomplete Fano matroid, minors K3, 3 and K5, an extra large cycle of occurrences are analyzed. An example of reconstructing a fragment of an incomplete Fano matroid with l-voids is considered. Examples are given for independent implementation of the method of filling the artificial intelligence database (AnwM f typeK) DB based on the results of the analysis of l-voids in the N-scheme of the Markov algorithm. The database is populated using a formal language with the alphabet M = litj/abdgckm where litj are terminal elements, abdgckm are non-terminal elements, and the basis of the alphabet is i – initial, t – terminal, j – isomorphic, l-empty morphisms. The p – initial, e – simple, and h – final occurrences of words from the Markov alphabet A are determined. An example of a simplified numbering of occurrence chains is given, which ensures the selection of all objects represented by words in the Markov alphabet A, belonging to “their own” chain of occurrences, as well as all related to chain object. The mechanism of dynamic change of the number-type in the N-scheme of the Markov algorithm is presented, which provides the analysis of the word as an evolving category, as well as the evolution of categories, which includes such a word. It has been established that normal Markov inference is characterized by temporal conditionality and locality. The conclusion is made about the expediency of considering the N-scheme in a distributed computing system. In this case, it is necessary to analyze the diagrams of occurrences of objects that have several designations with words from the Markov alphabet A, in order to identify them and process data from such objects.

First-order under-approximations of consistent query answers

Consistent Query Answering (CQA) is a principled approach for answering queries on inconsistent databases. The consistent answer to a query q on an inconsistent database db is the intersection of the answers to q on all repairs, where a repair is any consistent database that is maximally close to db. Unfortunately, computing consistent answers under primary key constraints has already exponential data complexity for very simple conjunctive queries, and is therefore completely impracticable.In this paper, we propose a new framework for divulging an inconsistent database to end users, which adopts two postulates. The first postulate complies with CQA and states that inconsistencies should never be divulged to end users. Therefore, end users should only get consistent query answers. The second postulate states that only those queries can be answered whose consistent answers can be obtained with low data complexity (i.e., by a polynomial-time algorithm or even a first-order logic query). User queries that exhibit a higher data complexity will be rejected.A significant problem in this framework is as follows: given a rejected query, find other queries, called under-approximations, that are accepted and whose consistent answers are contained in those of the rejected query. We provide solutions to this problem for the special case where the constraints are primary keys and the queries are self-join-free conjunctive queries.

Towards communication-efficient quantum oblivious key distribution

Oblivious Transfer, a fundamental problem in the field of secure multi-party computation is defined as follows: A database DB of N bits held by Bob is queried by a user Alice who is interested in the bit DB_b in such a way that (1) Alice learns DB_b and only DB_b and (2) Bob does not learn anything about Alice's choice b. While solutions to this problem in the classical domain rely largely on unproven computational complexity theoretic assumptions, it is also known that perfect solutions that guarantee both database and user privacy are impossible in the quantum domain. Jakobi et al. [Phys. Rev. A, 83(2), 022301, Feb 2011] proposed a protocol for Oblivious Transfer using well known QKD techniques to establish an Oblivious Key to solve this problem. Their solution provided a good degree of database and user privacy (using physical principles like impossibility of perfectly distinguishing non-orthogonal quantum states and the impossibility of superluminal communication) while being loss-resistant and implementable with commercial QKD devices (due to the use of SARG04). However, their Quantum Oblivious Key Distribution (QOKD) protocol requires a communication complexity of O(N log N). Since modern databases can be extremely large, it is important to reduce this communication as much as possible. In this paper, we first suggest a modification of their protocol wherein the number of qubits that need to be exchanged is reduced to O(N). A subsequent generalization reduces the quantum communication complexity even further in such a way that only a few hundred qubits are needed to be transferred even for very large databases.

A dichotomy in the complexity of counting database repairs

An uncertain database db is defined as a database in which distinct tuples of the same relation can agree on their primary key. A repair is obtained by selecting a maximal number of tuples without ever selecting two distinct tuples of the same relation that agree on their primary key. Obviously, the number of possible repairs can be exponential in the size of the database. Given a Boolean query q, certain (or consistent) query answering concerns the problem to decide whether q evaluates to true on every repair. In this article, we study a counting variant of consistent query answering. For a fixed Boolean query q, we define ♮CERTAINTY(q) as the following counting problem: Given an uncertain database db, how many repairs of db satisfy q? Our main result is that conjunctive queries q without self-join exhibit a complexity dichotomy: ♮CERTAINTY(q) is in FP or ♮P-complete.

Architecture, Design, Development, and Usage of ODBDetective 1.0

“ODBDetective is an Oracle database (Oracle) metadata mining tool for detecting violations of some crucial database (db) design, implementation, usage, and optimization best practice rules (bpr). This paper presents the set of bprs that is considered by the first full version (1.0) of ODBDetective, the db axioms from which they are derived, the corresponding tool’s facilities, and the essentials of its actual architecture, design, development, and usage, including the results of a case study on an Oracle production db. Moreover, even this first ODBDetective version also allows for storing semantic decision data on desired db scheme improvements, which will prove very useful to automatic improvement code generation in subsequent versions of this tool.”

On the consistent rewriting of conjunctive queries under primary key constraints

This article deals with the computation of consistent answers to queries on relational databases that violate primary key constraints. A repair of such inconsistent database is obtained by selecting a maximal number of tuples from each relation without ever selecting two distinct tuples that agree on the primary key. We are interested in the following problem: Given a Boolean conjunctive query q, compute a Boolean first-order (FO) query ψ such that for every database db , ψ evaluates to true on db if and only if q evaluates to true on every repair of db . Such ψ is called a consistent FO rewriting of q. We use novel techniques to characterize classes of queries that have a consistent FO rewriting. In this way, we are able to extend previously known classes and discover new ones. Finally, we use an Ehrenfeucht–Fraïssé game to show the non-existence of a consistent FO rewriting for ∃ x ∃ y ( R ( x ̲ , y ) ∧ R ( y ̲ , c ) ) , where c is a constant and the first coordinate of R is the primary key.

이중결정트리를 이용한 CCTV영상에서의 도로 날씨정보검출알고리즘 개발

본 논문에서는 도로 상에 설치된 CCTV의 영상정보에서 날씨정보를 검출하기 위한 방법으로 도로날씨정보 검출알고리즘을 제안한다. 도로 상의 CCTV 영상정보에서 날씨정보를 얻는 방법으로 맑은 날의 영상에서 RGB 평균값을 얻고 이를 기준으로 흐린 날 혹은 비 오는 날, 눈 오는 날, 안개 낀 날 등의 영상을 구분한다. 본 논문에서 제안하는 도로날씨정보 검출알고리즘은 많은 시간비용과 공간비용이 소모되는 날씨 데이터베이스를 활용하는 기존의 기법에 비하여, 시간비용과 공간비용이 적게 들기에 시스템을 구축함과 동시에 현장에 적용할 수 있다는 장점이 있다. 또한 본 알고리즘에서는 온 습도 정보와 일자 정보를 이용하여 검출된 날씨 정보를 재검증함으로 보다 정확한 날씨 정보를 검출할 수 있다. We proposed a detection scheme of weather information in CCTV video images in this paper. The scheme obtains the RGB distribution of shiny day and divide a target image into cloud, rain, snow and for RGB distributions. shiny day RGB distribution. Our scheme designed systematically to detection and separation special characteristics of images from complex weather information. Our algorithm has less overhead than the previous methods to use weather database DB at the view of time and space. And our algorithm can be use in real world system with low cost of implementation. Also, our algorithm use informations of temperature, humidity, date, and time to detect the information of weather with high quality.

Pharmacogenetic Analysis of Clinically Relevant Genetic Polymorphisms

The ascertainment of the human genome sequence has generated great enthusiasm for the use of gene-based approaches to improve virtually all aspects of medical care. Particular interest has focused on the field of pharmacogenetics--for example, the use of an individual's genetic profile to optimize drug prescription. This approach takes advantage of the presence of single-nucleotide polymorphisms (SNPs) or other genetic variants in every gene in the human genome. There are currently > 9 million SNPs in the human SNP database dbSNP, with an estimated 11 million variants ultimately to be found in the human population. To date, the preponderance of interest in this field has centered on the potential of applying this approach to subacute or chronic illnesses, such as cancer, cardiovascular disease, human immunodeficiency virus infection, or rheumatologic disorders. In contrast, little attention has been devoted to the potential utility of implementing the pharmacogenomic methodology for guiding drug selection for acutely ill patients in the critical care environment. Although such an approach has theoretical appeal as a means of enhancing quality and improving outcomes in this setting, several obstacles currently exist and slow the progress toward clinical application.

The creation of a database of odorous compounds focused on molecular rigidity and analysis of the molecular features of the compounds in the database.

It is important to select odorous molecules for experiments on olfaction and for the development of an electronic nose. Odorous molecules having a small number of conformers, namely structurally rigid molecules, are assumed to interact with a small number of types of olfactory receptor proteins or to interact with the proteins in a simpler manner than that of fairly flexible molecules. Focusing on the rigidity of molecular structures, we collected 287 odorous molecules from data sources, which included 1205 chemicals in total and a database of the 287 odorous molecules (DB_odMOL) was created using CS ChemFinder Pro (version 5.0). The logarithmic value of the octanol/water partition coefficient (log P) and melting point, boiling point and vapour pressure of the molecules were estimated using CS Chem3D Pro. The database DB_odMOL accumulates these estimated data in addition to literature values for odour quality, odour detection thresholds and the safety of molecules. The rigidity of the 287 molecules was further analysed by conformational analysis performed by molecular mechanics using Conformer in CS Chem3D Pro (version 5) and 72 rigid odorous molecules were selected. The 287 molecules were also analysed based on atomic composition, substructure and molecular size. Sixty-two odorous molecules among the 72 rigid odorous molecules were further selected based on their atomic composition. The 62 rigid molecules with simple atomic composition that were finally selected should be useful for researchers in choosing odorous molecules for the study of olfaction, including the fields of molecular biology, physiology, structure-odour relationships and other fields of the study concerning odour.

CIS1/336: Use of a Database Program to Convert Laboratory Information System (LIS) Data to Intranet Web Pages

IntroductionThe composition of Laboratory Ward Manuals is a time-consuming exercise. To keep manually prepared books up-to-date requires constant effort, amounting to several days or weeks of activity every year. As most of this information is found in the various tables of the usual Laboratory Information System (LIS), it should be possible to reformat this data into a form suitable for publishing on paper or on Web Pages. When the three hospitals in Saskatoon became part of a single operating entity, it became a necessity to redo the procedure manuals and ward manuals for all of the laboratories. As part of this exercise, we sought ways to minimize the work required. One method was to automate the ward manuals. Accordingly, an automated way of producing an Intranet ward manual was devised to reduce the work of the laboratory staff in this continuing endeavour.MethodsThe query language of the SoftLab LIS (SCC Clinical Information Systems, Palm Harbor, Fla, USA) was used to extract standard test data, including various descriptive terms, specimens required, minimum volumes, reference ranges, &c, &c in a comma-delimited form for input to a database application program. Paradox 8 (Corel Corporation) was used to build the several files necessary to hold the various forms of data from the many databases of the LIS. Paradox Macros were written to combine records from the various files into a single record containing concatenated strings to format the appropriate data in a form, which would display in a single column in the ultimate report. Using the standard Paradox report forms, HTML Web pages could then be generated which became available for publishing on the Hospital Intranet.ResultsThis procedure was used with the Saskatoon LIS to produce Intranet Web Pages, and also a print version of the Ward Manual). Once the Paradox Macros have been debugged, preparation of the updated Web Pages takes only a few minutes, and updates can be incorporated almost completely automatically.DiscussionSpread Sheet (SS) and Database (dB) Handlers have become highly flexible tools for generating many different types of reports, from almost any form of data. With the addition of HTML generation capabilities in the standard dB and SS application programs this becomes an even easier matter. This puts highly sophisticated Web Page generation capabilities into everyone's hands.

Complex objects: Theory and practice from a data- and knowledge engineering perspective, as seen in and from Yellowstone Park

Complex Objects as introduced by Bancilhon and Khoshafian, more than ten years ago, can be considered as extensions of tuples in a relational database. Their structure is a tree where the leaf nodes are constants and the inner nodes are either sets or tuples. There is one operation defined, ⩽, which determines whether one complex object is contained in another one. A query of the form: is a piece of information x contained in a database DB, can simply be formulated as ‘ x ⩽ DB’. On the basis of the ⩽ operation a lattice is defined. The lower upper bound of two complex objects x and ν is the operator, ‘+’ which will be shown to be equivalent to the operation ‘adding x to y’. Similarly a ‘∗’ operation being the greatest lower bound can be defined for two complex objects and determines the information common to the two objects. It will also be shown that rules can be introduced very easily. By means of this the notions of deductive databases and data mining can be defined in a natural way.

Verifying local stratifiability of logic programs and databases

In this paper, we deal with the problem of verifying local stratifiability of logic programs and databases presented by Przymusinski. The notion of dependency graphs is generalized from representing the priority relation between predicate symbols to representing the priority between atoms. Necessary and sufficient conditions for the local stratifiability of logic programs are presented and algorithms for performing the verification are developed. Finally, we prove that a database DB containing clauses with disjunctive consequents can easily be converted into a logic program P such that DB is locally stratified iff P is locally stratified.

Negation as failure: Careful closure procedure

The aim of this paper is a modification of Minker's Generalized Closed World Assumption that would allow application of the “negation as failure rule” with respect to a set P of (not necessarily all) predicates of a database DB. A careful closure procedure is introduced which, when applied to a database DB, produces a new database DB∗, that is used to answer queries about predicates from DB. It is shown that DB∗ is consistent iff DB is consistent. If P is the set of all predicates from DB and DB does not contain functional symbols, then DB∗ coincides with Minker's GCWA. The soundness and completeness of the careful closure procedure with respect to a minimal model style semantic is shown. As an inference engine associated with DB∗ we propose a query evaluation procedure QEP∗ which is a combination of a method of splitting an indefinite database DB into a disjunction of Horn databases and Clark's query evaluation procedure QEP. Soundness of QEP∗ with respect to DB∗ is shown for a broad class of databases.

Equality and Domain Closure in First-Order Databases

A class of first-order databases with no function signs is considered. A closed database DB is one for which the only existing individuals are those explicitly referred to in the formulas of DB. Formally, this is expressed by including in DB a domain closure axiom ( x ) x = c 1 ∨···∨ x = c p , where c 1 ,…, c p are all of the constants occurring in DB. It is shown how to completely capture the effects of this axiom by means of suitable generalizations of the projection and division operators of relational algebra, thereby permitting the underlying theorem prover used for query evaluation to ignore this axiom. A database is E-saturated if all of its constants denote distinct individuals. It is shown that such databases circumvent the usual problems associated with equality, which arise in more general databases. Finally, it is proved for Horn databases and positive queries that only definite answers are obtained, and for databases with infinitely many constants that infinitely long indefinite answers can arise.