Applied XML Programming for Microsoft .NET.pdf - Csbdu.in

In the next few sections of this chapter, you'll learn how to build a custom XML readerworking on top of comma-delimited CSV files.Mapping CSV Files to XMLA CSV file consists of one or more lines of text. Each line contains strings of textseparated by commas. Each line of a CSV file can be naturally associated with adatabase row in which each token maps to a column. Likewise, a line in a CSV file canalso be correlated to an XML node with as many attributes as the comma-separatedtokens. The following code shows a typical CSV file:Davolio,Nancy,Sales RepresentativeFuller,Andrew,Sales ManagerLeverling,Janet,Sales RepresentativeA good XML representation of this structure is shown here:Each row in the CSV file becomes a node in the XML representation, while each tokenis represented by a node attribute. In this case, the XML schema is ever-changingbecause the number of attributes varies with the number of commas in the CSV file.The number of total columns can be stored as an extra property. You can opt for anautomatically generated sequence of attribute names such as col1, col2, and so on, orif the CSV file provides a header with column names, you can use those names. Ofcourse, there is no way to know in advance, and in general, whether the first row has tobe read as the first data row or just the header. A possible workaround is adding anextra property that tells the reader how to handle the first row.Using the XML schema described so far, you can use the following pseudocode to readabout a given item of information in the second row:XmlCsvReader reader = new XmlCsvReader("employees.csv");reader.Read();reader.Read();Console.WriteLine(reader[1].Value);Console.WriteLine(reader["col2"].Value);Another reasonable XML schema for a CSV file is shown here:DavolioNancySales Representative46