2 using database object variables for programming
2。1 Advantages
ODBC2。0 can access the management functions in the program
Can control a variety of types of records set: Dynaset, Snapshop and Table record collection target
You can access stored procedures and queries actions
You can access the database collection, such TableDefs, Fields, Indexes and QueryDefs
Having a real transaction processing capabilities, including starting a transaction (Begintrans), commit the transaction (CommitTrans), and roll back the transaction (Rollback)
2。2 shortcomings
Than the method for encoding data usage controls large
Only indirect error handling and error recovery
Control of each database operation is not fine-grained
And the result set within the result set contains abundant resources of operating restrictions
With direct method using ODBC2。0API function compared to lower performance
2。3 Applications
Applications need to create tables, fields and indexes dynamically during execution。
Application involves synchronizing update several tables (but logically consistent) of complex transactions
Applications use the result set instead of Dynaset form (FORMS), such as Snapshots or Tables, here is the key design considerations
Table application is very large, more than 1000 records
Applications with complex data input / output terms, it involves many inter-related fields and includes a database referential integrity or consistency rules
Application needs to perform some additional operation and the result set of query processing, particularly the need for high data formatted display
Applications need to use complex ODBC management function to select, configure, and verify the establishment of various data sources
Application needs during the implementation of the "Display" The basic structure of the database
Application requires the use of complex multi-code indexing methods to retrieve or update records
B。原文的翻译
Visual Basic 语言与算法
1991年,美国微软公司推出了Visual Basic(可简称VB),目前的最新版本是VB 2008 Beta2(VB9)中文版。
Visual 意即可视的、可见的,指的是开发像windows操作系统的图形用户界面(Graphic User Interface,GUI)的方法,它不需要编写大量代码去描述界面元素的外观和位置,只要把预先建立好的对象拖放到屏幕上相应的位置即可。
Basic 实际上是一个短语的缩写,这个短语就是 Beginners all_purpose symbolic instruction code ,其中文意思为“初始者通用符号指令代码语言”。Visual Basic有学习版、专业版和企业版三种版本,以满足不同的开发需要。学习版适用于普通学习者及大多数使用Visual Basic开发一般Windows应用程序的人员,但是;专业版适用于计算机专业开发人员,包括了学习版的全部内容功能以及Internet控件开发工具之类的高级特性;企业版除包含专业版全部的内容外,还有自动化构件管理器等工具,使得专业编程人员能够开发功能强大的组骨子里分布式应用程序。
第1节Visual Basic的概述
Microsoft Visual Basic(简称VB)是在Windows操作平台下设计应用程序的最速度、最简捷的工具之一。不论是初学者还是专业开发人员,VB都为他们提供了一整套的工具,可以轻松方便的开发应用程序。因此,VB一直被作为大多数电脑初学者的首选入门编程语言。
“Visual”指的是采用可视化的开发图形用户界面(GUI)的方法,一般不需要编写大量代码去描述界面元素的外观和位置,而只要把需要的控件拖放到屏幕上的相应位置即可方便图形设计图形用户界面;“Basic”指的是 BASIC语言,因为VB是在原有的BAISC语言的基础上发展起来的。