巧用触发器实现学分的自动管理

触发器主要用于实现复杂数据完整性约束或业务规则。本文介绍了SQLServer数据库系统中,如何利用触发器实现学生成绩管理系统中学分的自动管理。     

浅析SQL SERVER 2005数据完整性技术控制与实现

SQL Server 2005是微软公司开发的大型关系数据库管理系统,为保证数据库数据完整性提供了重要技术,本文章主要从完整性约束、触发器两个技术阐述数据库系统中数据完整性控制和实现。     

巧用触发器实现学分的自动管理

触发器主要用于实现复杂数据完整性约束或业务规则。本文介绍了SQL Server数据库系统中，如何利用触发器实现学生成绩管理系统中学分的自动管理。     

基于Visual FoxPro的数据完整性剖析

主要对基于Visual FoxPro的关系型数据库中的数据完整性进行分析和应用.在关系数据库中,为保证数据的完整性,需要从关系的实体完整性、域完整性、参照完整性及触发器等几个方面进行约束和限制,即要设置主关键字、字段的有效性规则和关系表间的数据操作约束,从而保证数据的正确性和有效性,这也是关系型数据库特有的性能.     

基于VFP之DBMS数据完整性分析与应用

从DBMS之数据完整性出发,阐述了基于VFP之数据库管理应用系统中的各层次数据约束的含义和设计方法,最后说明了VFP中触发器的设计与应用,对MIS开发者有较好的参考价值。     

DML触发器实现数据完整性的应用研究

数据完整性是确保数据库数据安全的重要研究内容。通过DML触发器技术实现数据完整性控制,可有效防止由于对数据进行频繁的更新操作从而导致数据丢失或无效扩散。该文通过论述DML触发器的实现机制,并结合具体的开发实例,分析DML触发器在强制数据参照完整性、级联更新与删除、实现用户定义业务规则、更新不可更新视图等方面的应用基本步骤及设计技巧,反映了触发器应用在提高系统性能、简化数据库操作、维护数据完整性、有效性、增强数据库安全性、提高开发效率等方面的强大功能。     

DML触发器实现数据完整性的应用研究

数据完整性是确保数据库数据安全的重要研究内容。通过DML触发器技术实现数据完整性控制,可有效防止由于对数据进行频繁的更新操作从而导致数据丢失或无效扩散。该文通过论述DML触发器的实现机制,并结合具体的开发实例,分析DML触发器在强制数据参照完整性、级联更新与删除、实现用户定义业务规则、更新不可更新视图等方面的应用基本步骤及设计技巧,反映了触发器应用在提高系统性能、简化数据库操作、维护数据完整性、有效性、增强数据库安全性、提高开发效率等方面的强大功能。     

SQL触发器在旅行社管理信息系统中的应用

触发器是在数据库中数据表的特殊的存储过程,是数据库强制业务规则和数据完整性控制的一种主要机制。讨论了触发器在旅行社管理信息系统中的实际应用。     

SQL Sever 2000中基于触发器实现数据库的完整性

本文讨论了数据库完整性的定义,触发器的类型,并利用两个临时驻留在内存中的表:INSERTED表和DELETED表实现数据完整性操作中的事务操作.进而完成了在SQL Sever 2000中采用触发器来实现数据库的完整性,对相关的数据库完整性具有参考意义.     

关于MySQL数据库中触发器的学习探讨

触发器是一种特殊的存储过程,是数据库强制业务规则和控制数据完整性的一种主要方法。探讨了在MySQL数据库中通过触发器技术实现数据完整性控制机制,重点讨论了MySQL数据库中触发器的工作原理与实现过程,结合实例分析设计触发器的基本步骤。针对触发器这一数据库学习中的重点和难点,给出了在MySQL数据库中对触发器的理解和使用方法。     

触发器技术在数据库系统开发中的应用研究

如何保证数据的完整性是数据库系统设计与开发的重要内容之一,以医药销售管理系统为例,在SQL Server 2005的环境下,介绍了触发器技术在数据库系统中保证数据完整性所起的作用,实例研究证明,合理的触发器设计可以快速实现数据库系统的数据完整性、一致性,保证数据的同步.     

在关系数据库中构建数据完整性的检验策略

通过利用在关系型数据库中所提供的约束、默认、规则和嵌套触发器技术，对来自客户端的数据进行有效性和合法性的检验，有效地保证了数据源的正确性和完整性；此外，合理地定义和应用一项数据完整性的检验策略，可以更有效地提高数据存储和检索的效率。     

一个实时主动数据库的触发器机制

本文讨论了支持实时动数据库系统的触发器机制，包括触发器的概念，结构与说明及其监视执行模型。     

SQL Server触发器在保持数据库完整性中的应用

触发器在保持数据库的完整性与一致性方面起着非常重要的作用,它是一种保证数据库中数据完整性的方法。讲述了DML触发器的类型、工作机理及触发机制。以BBS论坛数据库为例,介绍了触发器在保持数据库完整性中的具体应用。     

Active Integrity Constraints for Database Consistency Maintenance

This paper introduces active integrity constraints (AICs), an extension of integrity constraints for consistent database maintenance. An active integrity constraint is a special constraint whose body contains a conjunction of literals which must be false and whose head contains a disjunction of update actions representing actions (insertions and deletions of tuples) to be performed if the constraint is not satisfied (that is its body is true). The AICs work in a domino-like manner as the satisfaction of one AIC may trigger the violation and therefore the activation of another one. The paper also introduces founded repairs, which are minimal sets of update actions that make the database consistent, and are specified and “supported” by active integrity constraints. The paper presents: 1) a formal declarative semantics allowing the computation of founded repairs and 2) a characterization of this semantics obtained by rewriting active integrity constraints into disjunctive logic rules, so that founded repairs can be derived from the answer sets of the derived logic program. Finally, the paper studies the computational complexity of computing founded repairs.     

Semantic integrity support in SQL:1999 and commercial (object-)relational database management systems

The correctness of the data managed by database systems is vital to any application that utilizes data for business, research, and decision-making purposes. To guard databases against erroneous data not reflecting real-world data or business rules, semantic integrity constraints can be specified during database design. Current commercial database management systems provide various means to implement mechanisms to enforce semantic integrity constraints at database run-time. In this paper, we give an overview of the semantic integrity support in the most recent SQL-standard SQL:1999, and we show to what extent the different concepts and language constructs proposed in this standard can be found in major commercial (object-)relational database management systems. In addition, we discuss general design guidelines that point out how the semantic integrity features provided by these systems should be utilized in order to implement an effective integrity enforcing subsystem for a database. Received: 14 August 2000 / Accepted: 9 March 2001 / Published online: 7 June 2001     

Processing negation and disjunction in logic programs through integrity constraints

Integrity constraints were initially defined to verify the correctness of the data that is stored in a database. They were used to restrict the modifications that can be applied to a database. However, there are many other applications in which integrity constraints can play an important role. For example, the semantic query optimization method developed by Chakravarthy, Grant, and Minker for definite deductive databases uses integrity constraints during query processing to prevent the exploration of search space that is bound to fail. In this paper, we generalize the semantic query optimization method to apply to negated atoms. The generalized method is referred to assemantic compilation. This exploration has led to two significant results. First, semantic compilation provides an alternative search space for negative query literals. The alternative search space can find answers in cases for which negation-as-finite-failure and constructive negation cannot. Second, we show how semantic compilation can be used to transform a disjunctive database with or without functions and denial constraints without negation into a new disjunctive database that complies with the integrity constraints.     

A path finding method for constraint checking in deductive databases

A method is presented for checking integrity constraints in a deductive database in which verification of the integrity constraints in the updated database is reduced to the process of constructing paths from update literals to the heads of integrity constraints. In constructing such paths, the method takes advantage of the assumption that the database satisfies the integrity constraints prior to the update. If such a path can be constructed, the integrity of the database has been violated. Correctness of the method has been proved for checking integrity constraints in stratified deductive databases. An explanation of how this method may be realised efficiently in Prolog is given.     

Global extensional assertions and local integrity constraints in federated schemata

Integrated access to multiple data sources requires a homogeneous interface provided by a federated schema. Such a federated schema should correctly reflect the semantics of the component schemata of which it is composed. Since the semantics of a database schema is also determined by a set of semantic integrity constraints, a correct schema integration has to deal with integrity constraints existing in the different component schemata. Traditionally, most schema integration approaches solely concentrate on the structural integration of given database schemata. Local integrity constraints are often simply neglected. Their relationship to global extensional assertions, which form the basic integration constraints, are even ignored completely. In this paper, we discuss the impact of global extensional assertions and local integrity constraints on federated schemata. In particular, we point out the correspondence between local integrity constraints and global extensional assertions. The knowledge about the correspondences between the given integrity constraints and extensional assertions can then be utilized for an augmented schema integration process.