基于SQL-92进行频集发现

关联规则挖掘是数据挖掘的主要分枝,频集发现是关联规则挖掘的重要阶段,该文主要讨论利用SQL-92进行频集发现的相关问题,并给出一种实现算法。     

Integrating Association Rule Mining with Relational Database Systems: Alternatives and Implications

Data mining on large data warehouses is becoming increasingly important. In support of this trend, we consider a spectrum of architectural alternatives for coupling mining with database systems. These alternatives include: loose-coupling through a SQL cursor interface; encapsulation of a mining algorithm in a stored procedure; caching the data to a file system on-the-fly and mining; tight-coupling using primarily user-defined functions; and SQL implementations for processing in the DBMS. We comprehensively study the option of expressing the mining algorithm in the form of SQL queries using Association rule mining as a case in point. We consider four options in SQL-92 and six options in SQL enhanced with object-relational extensions (SQL-OR). Our evaluation of the different architectural alternatives shows that from a performance perspective, the Cache option is superior, although the performance of the SQL-OR option is within a factor of two. Both the Cache and the SQL-OR approaches incur a higher storage penalty than the loose-coupling approach which performance-wise is a factor of 3 to 4 worse than Cache. The SQL-92 implementations were too slow to qualify as a competitive option. We also compare these alternatives on the basis of qualitative factors like automatic parallelization, development ease, portability and inter-operability. As a byproduct of this study, we identify some primitives for native support in database systems for decision-support applications.     

基于文件存储GIS的SQL解析器的设计与实现

针对利用文件存储的GIS系统不能自动实现查询这一问题，结合SQL-99标准和GIS软件MAPGIS定义的语法规则，运用编译原理中的词法分析、语法分析等理论，实现了将用户输入的普通查询表达式解释为一个标准的SQL语句，并输出查询结果。该SQL解析器已经成功地运用在MAPGIS文件管理的属性检索模块中。     

一种新的SQL注入防护方法的研究与实现

当前Wcb应用安全问题日益严峻,而SQI、注入是针对Wcb应用最为普遍的攻击手段之一。文中提出了一 种新的SQL注入防护方法。该方法通过将静态模式匹配与动态特征过滤配合使用,避免单一方法存在的不足,从而 达到良好的效果。该方法通过在安全环境下自动学习所有合法SQL语句,构建知识库;然后在实时工作环境下,利用 模式匹配算法将SQI、语句与知识库进行匹配,匹配成功则判定为合法SQI语句。对于匹配失败的SQI、语句并不立 即判定为非法,而是采用基于风险值的动态特征过滤算法进行深度特征检查,识别真正的非法SQL语句。基于本方 法,设计并实现了一个原型系统。测试结果表明,该原型系统具有较好的性能优势,并能够很好地解决一般防注入方 法带来的准确率与误报率之间的矛盾。     

新型SQL注入攻击的研究与防范

针对一种以HTTP Headers为途径的新型SQL注入攻击进行了深入研究.通过分析具体的SQL注入实例,揭示了该新型SQL注入攻击的原理,并提出了针对此类攻击的防范手段.通过ip过滤,数据校验,机器学习等手段建立了一套完整的防御模型,且该模型具有低侵入、易实现、高可用、强扩展等优点.     

MDBI查询预处理器的设计及实现

论述了ＭＤＢＩ查询预处理器的功能,并介绍了ＭＤＢＩ－ＳＱＬ语言。按照查询预处理的处理过程,分别描述了 ＭＤＢＩ查询预处理器中词法分析、语法分析、语义分析的设计和实现。     

T-SQL在图形设计中的应用

T-SQL是Microsoft SQL Server实现的语言,符合SQL-92标准。它是SQL Server开发人员的必备工具。本文用一个实例来说明T-SQL也能实现用数据库中的数据来进行图形设计。     

SQL DMO在Delphi中的应用

SQL Server拥有管理自身的强大能力,图形化管理工具MMC使得SQL Server管理员能够快速轻松地控制服务器的各个方面.这些工具的底层就是SQL-DMO（分布式管理对象）.SQL-DMO并不是一种新的数据库访问技术,他不关心数据库存储的信息,主要负责数据库本身的结构和维护,以及对包含数据库的SQL Server操作.SQL-DMO允许轻松地开发适合用户环境的定制SQL Server管理应用程序.使用SQL-DMO,可以使用Delphi或者其他OLE兼容语言来创建定制的SQL Server管理界面.该界面允许使用SQL Server企业管理器提供的功能.SQL-DMO允许应用程序执行通过那些SQL Server企业管理器手动实现的功能集.使用SQL-DMO,可以列出数据库和表、增加登陆帐户、控制复制、引入数据、引出数据以及执行其他管理任务.     

The CQL continuous query language: semantic foundations and query execution

CQL, a continuous query language, is supported by the STREAM prototype data stream management system (DSMS) at Stanford. CQL is an expressive SQL-based declarative language for registering continuous queries against streams and stored relations. We begin by presenting an abstract semantics that relies only on “black-box” mappings among streams and relations. From these mappings we define a precise and general interpretation for continuous queries. CQL is an instantiation of our abstract semantics using SQL to map from relations to relations, window specifications derived from SQL-99 to map from streams to relations, and three new operators to map from relations to streams. Most of the CQL language is operational in the STREAM system. We present the structure of CQL's query execution plans as well as details of the most important components: operators, interoperator queues, synopses, and sharing of components among multiple operators and queries. Examples throughout the paper are drawn from the Linear Road benchmark recently proposed for DSMSs. We also curate a public repository of data stream applications that includes a wide variety of queries expressed in CQL. The relative ease of capturing these applications in CQL is one indicator that the language contains an appropriate set of constructs for data stream processing. Edited by M. Franklin     

SQL生成器的设计与实现

编写复杂的SQL语句既耗费时间又容易出错,出现了许多SQL生成工具.现有的SQL生成工具大多缺乏完善的错误检测功能和良好的可扩展性.在吸收现有SQL生成工具优点的基础上设计了Select_SQL_Builder系统,它基于SQL92标准,实现了复杂的查询语句.系统对SQL语句进行了完整性、重复性和类型匹配等检查,并且把函数、表达式和条件作为对象,便于显示、修改、检查和生成SQL语句.同时经过简单的修改,系统能适应不同的数据库和增加更新语句、删除语句等功能.