SQL Server 2005及更早版本动态搜索条件高级技巧

需积分: 9 3 下载量 121 浏览量 更新于2024-07-31 收藏 432KB PDF 举报
本文档主要探讨的是如何在Microsoft SQL Server 2005及更早版本中实现动态搜索条件(Dynamic Search Conditions)的功能。这是在开发信息系统时常见的需求,用户需要能够根据多种可能的标准自由选择查询条件,而系统需要提供高效的响应时间,尤其是在处理普通搜索请求时。此外,代码的可维护性也是一个关键因素,以便应对不断变化的需求和功能更新。 作者Erland Sommarskog,一位备受尊敬的SQL Server MVP(Most Valuable Professional),分享了他在解决此类问题时所使用的技巧和策略。他的文章提供了一些深入的技术细节,这些内容可能在其他书籍和资料中不易找到,因此具有很高的实用价值。文章不仅涵盖了理论和实践,还考虑到了性能优化和代码设计的最佳实践。 文章分为介绍部分,详细阐述了动态搜索条件的重要性,以及它如何在满足用户需求的同时挑战开发者的技术能力。作者指出,要在保持查询性能、响应时间和代码清晰度之间找到平衡并非易事,特别是在处理大量可能的搜索参数时。 接下来,文章会介绍一系列技术解决方案,可能包括但不限于: 1. 使用动态SQL(Dynamic T-SQL):通过参数化查询或临时表来适应不同的搜索条件,这样可以避免SQL注入风险,并提高代码的复用性和可维护性。 2. 预编译语句(Prepared Statements):在编译阶段确定查询结构,只在运行时替换变量值,以提高执行效率。 3. 索引优化:针对常量或模式化的搜索条件,利用索引来加速查询速度。 4. 存储过程和视图:封装复杂的搜索逻辑,提供统一的接口,降低代码的复杂性。 5. 分页和结果集分块:限制每次返回的数据量,减轻服务器压力,改善用户体验。 6. 性能监控与调优:使用SQL Server Profiler或其他工具监控查询性能,进行必要的调整和优化。 7. 代码重构和设计模式:遵循DRY(Don't Repeat Yourself)原则,确保代码简洁、一致,易于扩展。 8. 版本适配:考虑到SQL Server 2005的特点,可能需要处理不同版本之间的差异和兼容性问题。 翻译版本方面,除了英文版由Erland Sommarskog撰写,还有由SQL Server MVP Jean-Pierre Riehl翻译的法文版和由Frank Kalis翻译的德文版,这体现了全球数据库专业人士对这一主题的广泛关注和跨语言的学习交流。 这篇文章是一个宝贵的资源,对于在SQL Server 2005及其之前版本中构建灵活且高效搜索功能的开发者来说,提供了丰富的技术和实践经验。无论你是初学者还是经验丰富的DBA,都能从中受益匪浅。

Before Playstation, there was Pong, at one time the ultimate in video game entertainment. For those of you not familiar with this game please refer to the Wikipedia entry (http://en.wikipedia.org/wiki/Pong) and the many fine websites extolling the game and its virtues. Pong is not so very different in structure from the Billiard ball simulation that you developed earlier in the course. They both involve a ball moving and colliding with obstacles. The difference in this case is that two of the obstacles are under user control. The goal of this project is to develop your own version of Pong in MATLAB using the keyboard as input, for example, one player could move the left paddle up and down using the q and a keys while the right paddle is controlled with the p and l keys. You may check the code for the Lunarlander game which demonstrates some of the techniques you can use to capture user input. You will also probably find the plot, set, line and text commands useful in your program. You have used most of these before in the billiard simulation and you can use Matlabs online help to get more details on the many options these functions offer. Your program should allow you to play a game to 11 keeping track of score appropriately. The general structure of the code is outlined below in pseudo code While not done Update Ball State (position and velocity) taking into account collisions with walls and paddles Check for scoring and handle appropriately Update Display Note that in this case it is implicitly assumed that capturing the user input and moving the paddles is being handled with callback functions which removes that functionality from the main loop. For extra credit you could consider adding extra features like spin or gravity to the ball flight or providing a single player mode where the computer controls one of the paddles.

2023-05-30 上传