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Application of recursive query on Structured query Language Server

Journal of Donghua University(English Edition) 2023年第1期40卷 68-73页

作者：荀雪莲 ABHIJIT Sen 姚志强 Library North China Institute of Aerospace EngineeringLangfang 065000China Department of Computer Science&Information System Kwantlen Polytechnic UniversitySurreyCanada School of Computer Science and Engineering North China Institute of Aerospace EngineeringLangfang 065000China

The advantage of recursive programming is that it is very easy to write and it only requires very few lines of code if done *** query language(SQL)is a database language and is used to manipulate *** Microsoft SQL Server 2000,recursive queries are implemented to retrieve data which is presented in a hierarchical format,but this way has its *** table expression(CTE)construction introduced in Microsoft SQL Server 2005 provides the significant advantage of being able to reference itself to create a recursive *** data structures,organizational charts and other parent-child table relationship reports can easily benefit from the use of recursive *** recursive query is illustrated and implemented on some simple hierarchical *** addition,one business case study is brought forward and the solution using recursive query based on CTE is *** the same time,stored procedures are programmed to do the recursion in *** results show that recursive queries based on CTEs bring us the chance to create much more complex queries while retaining a much simpler syntax.

关键词： structured query language(SQL)server common table expression(CTE) recursive query stored procedure hierarchical data

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Research On recursive query Over XML Data Stream Based On Pushdown Automation

Research On Recursive Query Over XML Data Stream Based On Pu...

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2010 International Conference on Intelligent Computing and Integrated Systems

作者： ZHANG Xiao-lin. Information Engineering College Inner Mongolia University of Science and Technology Batou,China LU Hao Information Engineering College Inner Mongolia University of Science and Technology Batou,China

For descendant axis(//) and predicate([]) structural features of XPath with different depths of the XML data stream recursive query processing problem,a method based on pushdown automation is *** made the kinds of step transform into the corresponding processing modules,then these modules are combined by the algorithm,the top-down tree query model is *** the multi-match will occurred in the query processing,which will produce a large number of matching patterns,the model save and check those matching modules by the effective matching strategy and cache operating,successfully completed the recursive query over XML data ***,the experimental results show that the proposed method is better than the traditional method.

关键词： XML data stream multiple matching pushdown automation recursive query tree query model

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Towards Set-oriented recursive XML query in Pattern-based Logic Views

Towards Set-oriented Recursive XML Query in Pattern-based Lo...

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2013 IEEE 4th International Conference on Software Engineering and Service Science

作者： Peng Wen Shi Ying Xuhui Li Libing Wu Rui Cai School of Information Management Wuhan University State Key Lab of Software Engineering Computer SchoolWuhan University

ISBN: (纸本)9781467349994

recursive query is an interesting and subtle topic in XML *** XML query languages often resort to recursive function or recursive predicate to present recursive XML ***,this approach implicitly adopts a tuple-oriented way to query processing which is not fit for the set-oriented data processing in *** this paper,we propose a new approach to presenting recursive XML query in a pattern-based logic view named *** deploys conjunctive and disjunctive operators to compose tree-like patterns,which can expressively specify the logic semantics in XML *** the assistance of the descendant operator,the syntactic and semantic mechanisms of CDV,the recursive XML query can be easily presented in a set-oriented *** demonstrate the usage and advantage of the CDV in typical recursive queries.

关键词： XML query query language recursive query

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Visualization of recursive Database-query Output using a Declarative System: An Illustration through Parts-Assembly Tree Visualization 5

Visualization of Recursive Database-Query Output using a Dec...

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IEEE 5th International Conference for Convergence in Technology (I2CT)

作者： Rohil, Mukesh Kumar Gupta, Neetika Birla Inst Technol & Sci Dept Comp Sci & Informat Syst Pilani 333031 Rajasthan India

ISBN: (数字)9781538680759

ISBN: (纸本)9781538680759

For visualization of output of database queries, the trial charts like bar graphs, line graphs, scatter plots and pie-charts are inappropriate even for small data set when the results of a query are generated recursively in the form of a graph or tree structure. Most of the recursive queries are used to retrieve hierarchical relationships among the instances of data within the database tables. Certain constraints are better represented by recursive rules. SQL 1999 standards allow the recursive queries using recursive common table expressions. To write these queries, views of relations have to be defined in terms of same table multiple times making procedural solutions less desirable. Datalog is also used for recursive queries. Since execution of most of the recursive queries can be represented by a syntax tree, therefore their output in most of the application scenarios is a tree. There is no support in SQL 1999 and Datalog to visualize output generated by recursive queries. In this research, the authors present visualization of output in two forms: First, an interactive tree view, and second, a complete non-interactive view of the output in the form of a tree. The correct results obtained from the system suggest that if software developers take care of appropriate ordering of the predicates, Prolog (PROgramming in LOGic) can be a better option over Datalog because Prolog provides many built-in predicates and many of its features make it suitable as a relational language.

关键词： Information Systems Data Visualization recursive query Declarative System Prolog Programming

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A Case for Stale Synchronous Distributed Model for Declarative recursive Computation

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THEORY AND PRACTICE OF LOGIC PROGRAMMING 2019年第5-6期19卷 1056-1072页

作者： Das, Ariyam Zaniolo, Carlo Univ Calif Los Angeles Dept Comp Sci Los Angeles CA 90024 USA

A large class of traditional graph and data mining algorithms can be concisely expressed in Datalog, and other Logic-based languages, once aggregates are allowed in recursion. In fact, for most BigData algorithms, the difficult semantic issues raised by the use of non-monotonic aggregates in recursion are solved by Pre-Mappability (PreM), a property that assures that for a program with aggregates in recursion there is an equivalent aggregate-stratified program. In this paper we show that, by bringing together the formal abstract semantics of stratified programs with the efficient operational one of unstratified programs, PreM can also facilitate and improve their parallel execution. We prove that PreM-optimized lock-free and decomposable parallel semi-naive evaluations produce the same results as the single executor programs. Therefore, PreM can be assimilated into the data-parallel computation plans of different distributed systems, irrespective of whether these follow bulk synchronous parallel (BSP) or asynchronous computing models. In addition, we show that non-linear recursive queries can be evaluated using a hybrid stale synchronous parallel (SSP) model on distributed environments. After providing a formal correctness proof for the recursive query evaluation with PreM under this relaxed synchronization model, we present experimental evidence of its benefits.

关键词： Datalog Deductive Databases recursive query Stale Synchronous Parallel Model Bulk Synchronous Parallel Model Parallel and Distributed Computing

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Counting and Topological Order

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Journal of Computer Science & Technology 1997年第6期12卷 497-509页

作者：陈阳军 Technical Institute of Changsha Changsha

The counting method is a simple and efficient method for processing linear recursive datalog queries. Its time complexity is bounded by O(n.e), where n and e denote the numbers of nodes and edges, respectively, in the graph representing the input relations. In this paper, the concepts of heritage appearance function and heritage selection function are introduced, and an evaluation algorithm based on the computation of such functions in topological order is developed. This new algorithm requires only linear time in the case of non-cyclic data.

关键词： recursive query counting topological order heritage function

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The SQL Function XMLNEST to Generate recursive XML Values from Relational Data

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JOURNAL OF INFORMATION SCIENCE AND ENGINEERING 2011年第4期27卷 1283-1302页

作者： Park, Sung-Chul Park, Young-Chul Yeungjin Coll Sch Comp Informat Taegu 702721 South Korea Kyungpook Natl Univ Sch Comp Taegu 702701 South Korea

SQL standard provides SQL/XML publishing functions to publish the result of an SQL query as XML values but it does not provide any SQL/XML publishing function that can publish the result of a recursive SQL query as recursively structured XML values. Therefore, to publish transitively connected relational tuples as recursively structured XML values with the use of appropriate SQL/XML publishing functions, we have to write a nested SQL query. Writing that query, however, is not easy provided that the depth of the connections is deep even if we know the depth of them and is not possible once the depth of the connections is not known in advance. To solve the problem, we propose a new SQL function XMLNEST that can publish the result of a recursive SQL query as recursively structured XML values. Both the recursive structure and the order of sibling XML elements of the XML values can be specified in the invocation of XMLNEST. Our experiments show that the proposed scheme will be the unique reasonable solution to the problem.

关键词： XML schema graph Xquery SQL/XML publishing function recursive query nested query recursive XML values SQL aggregate function XMLNEST

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Magic Sets Revisited

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Journal of Computer Science & Technology 1997年第4期12卷 346-365页

作者：陈阳军 Technical Institute of Changsha Changsha

This paper distinguishes among three kinds of linear recursions: canonical strongly linear recursion (CSLR), non-interdependent linear recursion (NILR) and interdependent linear recurstion (ILR) and presents an optimal algorithm for each. First, for the CSLRs, the magic-set method is refined in such a way that queries can be evaluated efficiently. Then, for the NILRS and ILRs, the concept of query dependency graphs is introduced to partition the rules of a program into a set of CSLRs and the computation is elaborated so that the oplimization for CSLRs can also be applied.

关键词： Deductive database recursive query magic set query graph bottom-up evaluation.

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Processing recursive Xquery over XML streams: The Raindrop approach

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DATA & KNOWLEDGE ENGINEERING 2008年第2期65卷 243-265页

作者： Wei, Mingzhu Rundensteiner, Elke A. Mani, Murall Li, Ming Worcester Polytech Inst CS Dept Worcester MA 01609 USA

XML stream applications bring the challenge of efficiently processing queries on sequentially accessible token-based data. For efficient processing of queries, we need to ensure that memory usage stays low. This in turn requires that we avoid holding data in the query buffer, by outputting it at the earliest possible time. In this paper, we propose a new class of stream algebra operators for efficient recursive Xquery stream processing. Our plan generator will analyze the query, and the schema when available to determine which join operators in the query need recursive join support and thus can plug in the more inexpensive just-in-time structural join whenever possible. In particular, we propose two strategies for implementing structural joins: (a) the just-in-time structural join strategy efficiently processes joins over non-recursive XML token streams;and (b) the recursive structural join strategy supports structural joins over recursive XML sub-streams, however, at an added cost of generating and comparing tuple-level ID. Both structural join strategies are complemented by an automata-driven invocation mechanism that triggers the execution of each join process at the first possible moment upon recognizing the end of the targeted input stream subelement. Further, we design this StructuralJoin operator itself to be context-aware. The operator is capable of at run-time switching from the efficient just-in-time join strategy for elements that are recognized to be non-recursive to the more powerful ID-based structural join strategy for elements that are identified to be recursive. We incorporate the proposed techniques into the Raindrop stream engine. We also report on experimental studies we conducted using the ToXgene benchmark that demonstrate that the performance improvements of the techniques. (C) 2007 Elsevier B.V. All rights reserved.

关键词： XML query optimization Xquery processing recursive query structural join

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Optimization of Linear recursive Queries in SQL

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IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING 2010年第2期22卷 264-277页

作者： Ordonez, Carlos Univ Houston Dept Comp Sci Houston TX 77204 USA

Recursion is a fundamental computation mechanism which has been incorporated into the SQL language. This work focuses on the optimization of linear recursive queries in SQL. query optimization is studied with two important graph problems: computing the transitive closure of a graph and getting the power matrix of its adjacency matrix. We present SQL implementations for two fundamental algorithms: Seminaive and Direct. Five query optimizations are studied: 1) Storage and indexing;2) early selection;3) early evaluation of nonrecursive joins;4) pushing duplicate elimination;and 5) pushing aggregation. Experiments compare both evaluation algorithms and systematically evaluate the impact of optimizations with large input tables. Optimizations are evaluated on four types of graphs: binary trees, lists, cyclic graphs, and complete graphs, going from the best to worst case. In general, Seminaive is faster than Direct, except for complete graphs. Storing and indexing rows by vertex and pushing aggregation work well on trees, lists, and cyclic graphs. Pushing duplicate elimination is essential for complete graphs, but slows computation for acyclic graphs. Early selection with equality predicates significantly accelerates computation for all types of graphs.

关键词： recursive query SQL query optimization transitive closure

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