ASP.NET2.0中利用C#实现DBF文件向MDB文件的转换

本文以C#为设计语言,应用ADO.NET技术,并且综合运用DataAdapter与DataSet,完成ASP.NET下DBF文件向MDB文件的转换,这样在应用系统中无需借助第三方软件的转换就可以直接使用DBF文件,解决了以MDB文件为数据源的应用系统如何直接使用DBF文件的问题。     

如何将DBF转换成CSV文件

在很多学校中仍然有一些比较古老的数据库，比如说几年前在FoxPro环境下编制的DBF文件。现在要进行信息化管理，统一迁移到微软的Office办公平台，这涉及到文件格式转换的问题。在网上可以找到一些软件，包括：DBF to MDB ConverterDBF to CSV Converter，DBF to XLS Converter。但这些都是付费软件，试用版只能转换50条记录。在网上搜索到一些DBF文件格式的文档，适用于dbaseiii＋，dbaseiv，foxbase，foxpro2．6以上版本。结合当前的文件，用UltraEdit分析一下，可以发现一些内在规律，整个文件由三部分组成：第1部分：文件头；第2部分：所有字段定义的集合，主要包含名称，类型，偏移，长度等等；第3部分：所有记录的集合。     

BASIC随机数据文件向数据库DBF文件的转换

BASIC和数据库(DBASE、F-OXBASE)都是交互性语言软件,功能丰富,使用方便,应用十分广泛.工作中有时需要将BASIC的数据文件转换为数据库的DBF数据文件.BASIC的顺序数据文件(用WRITE语句生成)可以直接进行这种转换,随机数据文件则不能.而BASIC的数据文件中,大量都是随机文件.为     

BASIC随机数据文件向数据库DBF文件的转换

BASIC和数据库(DBASE、FOXBASE)都是交互性语言软件,功能丰富,使用方便,应用十分广泛。工作中有时需要将BASIC的数据文件转换为数据库的DBF数据文件。BASIC的顺序数据文件(用WRITE语句生成)可以直接进行这种转换,随机数据文件则不能。而BASIC的数据文件中,大量都是随机文件。为了解决此问题,笔者探索出两种转换方法,概述如下。 设BASIC的随机文件含有三个字段,宽度分别为6、2、6;共四个记录;文件名为SD.DAT。转换前,先建一个相应格式的数据库DBF头文件(即记录数为零的空库,设库名为DD.DBF)。 方法一:用APPEND语句进行转换。它要求待转换的数据文件必须是符合一定格式的文本文件,即每个字段用双引号括起来,字段之间用逗号分隔,第一行由回车换行结束,文件结束符为1AH。为此,用程序一     

基于ASP．NET2．0的文件上传研究

在浏览器,服务器的应用环境中,文件上传技术是一个很实用的技术,有着很广泛的应用。木文主要介绍了基于ASP．NET2．0的文件上传及上传文件时需要注意的事项。     

.NET环境的文件对话框设计

本文通过一个完整的实例,演示了.NET环境下如何使用Directory类和DirectoryInfo类,完成文件对话框的设计,较好地解决了.NET下磁盘目录的遍历问题,可直接应用于ASP.NET的应用系统中。     

BASIC读取DBASEⅢ内存变量文件的方法

BASIC 直接操作 DBASEⅢ数据库 DBF 文件的方法已有许多文章论及,但在 DBASEⅢ中经常有些控制参数或其它辅助参数需要传送,对于这些参数用DBF 文件传送起来不太方便,而内存变量文件(MEM 文件)实现这些参数的传送是较合适的。为此,在 BASIC 直接操作 DBF 文件的同时,还应考虑如何操作 MEM文件。本文对 MEM 文件的结构作了分析,得出了 BASIC 读取 DBASEⅢ内存变量文件的方法。     

Text转换为Access MDB

Text文件类型在很多软件中都为一般应用程序与数据库之间架起一座桥梁，你可以使用Text ISAM驱动程序和SQL来把Text文件转换成Access MDB数据库文件。首先为文本文件创建一个SCHEMA．INI文件，然后使用下面的代码来实现转换：     

MIS数据库文件头损坏的修复

在MIS中,使用最多的文件类型就算是DBF文件了,因为该文件是最通用的数据库文件,各种系统都可以使用该结构,如:dBASE Ⅲ,FoxBase,Cliper,Foxpro等,目前使用比较多的是Foxpro系统编制的MIS。在MIS应用中,数据库文件损坏是很难避免的,因而对损坏的数据库文件的修复和抢救重要数据成为MIS应用中的一个重要的组成部分。     

SQL/DS表文件转换成DBF文件的实践

本文作为《DBF文件装入到SQL/DS表文件的实践》一文的补充,全面地、详尽地分析了SQL/DS数据库表文件和DBASE-Ⅲ数据库DBF文件的文件组织形式与存贮结构。并且通过分析,提出了一种把IBM-4381机中的SQL/DS表文件转换成微机上的DBASE-ⅢDBF文件的方法。以便使这两种不同类型的数据库可以共享数据     

ASP下的常用数据库存取技术的实现

该文讨论利ASP下存取DBF、DBC、MDB、Excel、SQL Server类型数据的方法及函数实现,对企事业数据重用及共享具有很强的实际意义。     

基于ASP．NET技术的Web应用系统安全机制分析与设计

本文重点探讨基于ASP.NET技术开发Web应用系统的安全问题.分析了用ASP.NET技术开发Web应用系统易产生的安全隐患,对操作系统、开发平台和数据库之间的安全协作机制进行了分析,并重点讨论了数据库资源的保护问题,最后以一个文档管理系统为例,具体说明了如何实现对数据库资源的安全访问.     

Table form document analysis based on the document structure grammar

Structure analysis of table form documents is an important issue because a printed document and even an electronic document do not provide logical structural information but merely geometrical layout and lexical information. To handle these documents automatically, logical structure information is necessary. In this paper, we first analyze the elements of the form documents from a communication point of view and retrieve the grammatical elements that appear in them. Then, we present a document structure grammar which governs the logical structure of the form documents. Finally, we propose a structure analysis system of the table form documents based on the grammar. By using grammar notation, we can easily modify and keep it consistent, as the rules are relatively simple. Another advantage of using grammar notation is that it can be used for generating documents only from logical structure. In our system, documents are assumed to be composed of a set of boxes and they are classified as seven box types. Then the box relations between the indication box and its associated entry box are analyzed based on the semantic and geometric knowledge defined in the document structure grammar. Experimental results have shown that the system successfully analyzed several kinds of table forms.     

A new document representation using term frequency and vectorized graph connectionists with application to document retrieval

This paper presents a new document representation with vectorized multiple features including term frequency and term-connection-frequency. A document is represented by undirected and directed graph, respectively. Then terms and vectorized graph connectionists are extracted from the graphs by employing several feature extraction methods. This hybrid document feature representation more accurately reflects the underlying semantics that are difficult to achieve from the currently used term histograms, and it facilitates the matching of complex graph. In application level, we develop a document retrieval system based on self-organizing map (SOM) to speed up the retrieval process. We perform extensive experimental verification, and the results suggest that the proposed method is computationally efficient and accurate for document retrieval.     

XML加密及其在电子公文中的应用

可扩展标记语言XML正逐渐成为分布式计算的通用语言.随着XML的广泛应用,XML数据的安全问题已成为关注的焦点.分析了XML加密规范.基于NET平台,通过把C#语言和XML加密规范有机地结合起来,实现了XML加密系统.该系统能够对XML文档、XML元素以及任意二进制数据加密.利用公钥基础设施PKI技术,把XML加密应用于电子公文,保证了电子公文的安全.     

Automatic document classification and indexing in high-volume applications

In this paper a system for analysis and automatic indexing of imaged documents for high-volume applications is described. This system, named STRETCH (STorage and RETrieval by Content of imaged documents), is based on an Archiving and Retrieval Engine, which overcomes the bottleneck of document profiling bypassing some limitations of existing pre-defined indexing schemes. The engine exploits a structured document representation and can activate appropriate methods to characterise and automatically index heterogeneous documents with variable layout. The originality of STRETCH lies principally in the possibility for unskilled users to define the indexes relevant to the document domains of their interest by simply presenting visual examples and applying reliable automatic information extraction methods (document classification, flexible reading strategies) to index the documents automatically, thus creating archives as desired. STRETCH offers ease of use and application programming and the ability to dynamically adapt to new types of documents. The system has been tested in two applications in particular, one concerning passive invoices and the other bank documents. In these applications, several classes of documents are involved. The indexing strategy first automatically classifies the document, thus avoiding pre-sorting, then locates and reads the information pertaining to the specific document class. Experimental results are encouraging overall; in particular, document classification results fulfill the requirements of high-volume application. Integration into production lines is under execution. Received March 30, 2000 / Revised June 26, 2001     

A framework for variable content document generation with multiple actors

ContextAdvances in customization have highlighted the need for tools supporting variable content document management and generation in many domains. Current tools allow the generation of highly customized documents that are variable in both content and layout. However, most frameworks are technology-oriented, and their use requires advanced skills in implementation-related tools, which means their use by end users (i.e. document designers) is severely limited.ObjectiveStarting from past and current trends for customized document authoring, our goal is to provide a document generation alternative in which variants are specified at a high level of abstraction and content reuse can be maximized in high variability scenarios.MethodBased on our experience in Document Engineering, we identified areas in the variable content document management and generation field open to further improvement. We first classified the primary sources of variability in document composition processes and then developed a methodology, which we called DPL – based on Software Product Lines principles – to support document generation in high variability scenarios.ResultsIn order to validate the applicability of our methodology we implemented a tool – DPLfw – to carry out DPL processes. After using this in different scenarios, we compared our proposal with other state-of-the-art tools for variable content document management and generation.ConclusionThe DPLfw showed a good capacity for the automatic generation of variable content documents equal to or in some cases surpassing other currently available approaches. To the best of our knowledge, DPLfw is the only framework that combines variable content and document workflow facilities, easing the generation of variable content documents in which multiple actors play different roles.     

A survey of document image classification: problem statement,classifier architecture and performance evaluation

Document image classification is an important step in Office Automation, Digital Libraries, and other document image analysis applications. There is great diversity in document image classifiers: they differ in the problems they solve, in the use of training data to construct class models, and in the choice of document features and classification algorithms. We survey this diverse literature using three components: the problem statement, the classifier architecture, and performance evaluation. This brings to light important issues in designing a document classifier, including the definition of document classes, the choice of document features and feature representation, and the choice of classification algorithm and learning mechanism. We emphasize techniques that classify single-page typeset document images without using OCR results. Developing a general, adaptable, high-performance classifier is challenging due to the great variety of documents, the diverse criteria used to define document classes, and the ambiguity that arises due to ill-defined or fuzzy document classes.     

PDF文档的跨终端发布技术

围绕目前出版社在对数字化内容进行跨终端发布时遇到的问题,重点对PDF文档的版面信息抽取和跨终端自适应重组等技术进行研究,提出了针对PDF文档中文本、图片等信息的抽取方法和版面结构分析方法,利用终端自适应重组算法对数字化内容进行跨终端发布;以此为基础设计了一套数字内容跨终端发布的系统,并应用在出版社的实际工作中,实验结果证明了方案的可行性。