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SQL Server 2005中触发器的应用 总被引：1，自引：0，他引：1
触发器是一种保证数据完整性的方法,它是一种特殊的存储过程,本文简述了SQL Server 2005中的重种触发器对象：After,DDL和Instead of触发器的概念、工作原理,并给出了应用实例。 相似文献
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触发器是VFP为应用程序开发人员提供的一种保证数据库中数据完整性的一种方法。本文介绍了VFP中触发器的概念及创建方法,并给出了触发器在控制数据完整性方面的应用实例。 相似文献
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触发器是数字电路中的一个重要单元电路,是组成时序逻辑电路的重要单元。并且触发器按功能可以分为RS触发器、JK触发器、D触发器、T触发器等;按组成结构可以分为基本结构触发器、同步结构触发器、主从结构触发器、边沿结构触发器等。这样的话,关于触发器可以组合成很多类型,如同步JK触发器、基本RS触发器、边沿D触发器等,为了简化教学,我们可以把这些触发器电路中相同功能、不同结构的电路进行简化分析。 相似文献
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在数字电路中,触发器是一种基本的逻辑记忆单元,具有的两种逻辑状态分别为0和1,即通常所说的没电或有电。电路中的触发器所具备的功能主要有三种,包括恢复功能、屏蔽功能、记忆功能,其中最为重要的是记忆信号功能,这也是构成时序电路最为基本的逻辑单元。为了进一步对数字电路触发器的应用进行分析,文章以智力竞赛抢答器设计为例,对抢答器电路中的触发器功能及运用进行了认识和探究。 相似文献
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JK触发器是数字电路中应用最广功能最强大的一类触发器，但其结构有其特定的规律，不存在同步触发器。有些教材只凭想象，凭空捏造，一必须加以澄清。 相似文献
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触发器是一种特殊类型的存储过程,由T-SQL语句组成。它与表紧密相连,但是具有自己显著的特点。本文介绍了三种类型的触发器,并结合具体的应用实例说明它们的用法。 相似文献
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总结基本RS触发器、同步RS触发器、主从RS触发器和主从JK触发器等不同电路结构触发器的动作特点,特别对不定态、空翻．一次翻转等进行讨论．以便学生理解和记忆。 相似文献
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分析了主从触发器的逻辑结构，提出了主从触发器由特征锁存器和通用锁存器构成的设计模式．基于这一模式，用限幅电压开关理论指导设计了ｎＭＯＳ三值Ｄ型、ＪＫＬ型和Ｔ型主从触发器．结果表明，这一设计模式可克服ＪＫＬ型和Ｔ型通过Ｄ型主从触发器转换得到的缺点，并且证明了限幅电压开关理论可在开关级指导触发器设计 相似文献
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本文介绍在使用IB数据库开发程序过程中,使用其触发器与生成子功能实现自动增长数据类型的方法. 相似文献
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Due to the special characteristics and challenges in Chinese language, event extraction in Chinese is much more difficult than that in English. In particular, the state-of-the-art Chinese event extraction systems suffer much from the low recall in trigger identification due to the failure in identifying unknown triggers and the inconsistency in identifying trigger mentions. To resolve these two issues, this paper proposes an inference mechanism to infer unknown triggers via the compositional semantics inside Chinese words and another inference mechanism to recover trigger mentions via the discourse consistency between Chinese trigger mentions. Here, various morphological structures are explored to better represent the compositional semantics inside Chinese triggers and automatically identify the head morpheme as the governing sememe of a trigger in inferring unknown triggers. Evaluation on the ACE 2005 Chinese corpus justifies the effectiveness of our approach over a strong baseline in Chinese event extraction, in particular trigger identification. 相似文献
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The aim of this study was to investigate videos as potential triggers of behavior. Therefore, we applied the theories of triggers and media richness to learn about the triggering efficiency of mobile marketing videos on participants’ behavioral intentions. The experiment involved three distinct test groups, each comprising 41 student participants. From the perspective of media richness theory, we observed that the different kinds of videos had quite similar effects in terms of triggering behavioral changes. However, the mechanisms explaining why triggers were present differed for each video. Further, the results reveal that the consumer's position in the information search process was the most significant reason for the triggering of any kind of effect. In addition, the instructionally designed videos were able to exert an affective triggering effect: the more participants liked the video, the more it affected their participation intention and recall scores. This study extends the media richness research by demonstrating that the effects of media richness can vary within technically similar videos, as they form different logical connections among non-verbal visual cues related to a video's storyline. 相似文献
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Multidisciplinary teams are an essential aspect of modern organizational work. These teams often work in information-rich environments but little is known about their collaborative information seeking (CIS) behavior. We have been studying the CIS behavior of teams in the context of medical care. We conducted an ethnographic field study of a multidisciplinary patient care team in an emergency department to identify (a) team information needs and (b) situations that trigger collaborative information seeking activities. We identified seven categories of information needs as expressed by questions asked by team members. The majority of questions focused on medical information, but there were a larger than expected percentage of questions focusing on organizational information. We also identified three triggers for CIS activities. These triggers are: (1) lack of expertise, (2) lack of immediately accessible information, and (3) complex information needs. The questions and triggers highlight the importance of face-to-face communication during CIS activities and how CIS activities could lead to interruptive workplaces. We also discuss organizational and technical implications for supporting CIS behavior of teams. 相似文献
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Collaborative information behavior is an essential aspect of organizational work; however, we have very limited understanding of this behavior. Most models of information behavior focus on the individual seeker of information. In this paper, we report the results from two empirical studies that investigate aspects of collaborative information behavior in organizational settings. From these studies, we found that collaborative information behavior differs from individual information behavior with respect to how individuals interact with each other, the complexity of the information need, and the role of information technology. There are specific triggers for transitioning from individual to collaborative information behavior, including lack of domain expertise. The information retrieval technologies used affect collaborative information behavior by acting as important supporting mechanisms. From these results and prior work, we develop a model of collaborative information behavior along the axes of participant behavior, situational elements, and contextual triggers. We also present characteristics of collaborative information system including search, chat, and sharing. We discuss implications for the design of collaborative information retrieval systems and directions for future work. 相似文献
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This paper proposes a design framework of sensor communication by using the stochastic event triggers, which aims at best saving the communication resources. The system to be considered is as follows: a sensor takes measurements of the states of a dynamic process and sends the information to a remote estimator, and the estimator computes the state estimates for the dynamic process. To save communication resources, a set of stochastic event triggers on the measurements are assigned to the sensor. At each sampled time, when no trigger is triggered, the sensor sends nothing to the estimator; when one of them is triggered, the sensor sends the identity code of the corresponding trigger. It is shown that once the estimator receives the identity of the trigger, it is equivalent for the estimator to receiving a measurement from a certain virtual sensor. Based on it, the system performance under the proposed communication is analyzed, and the design of specific models is considered. Examples are presented to demonstrate the proposed communication design. 相似文献
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在将现有数据库从SQL Server移植到DB2时，由于DB2不支持SQL Server的级联更新的特性，该功能在DB2中的实现成为一个棘手问题。本文介绍了一种通过增加触发器来模拟主外键，实现级联更新功能的方法。该方法在大多数场合下适用。 相似文献