Flat and XML file formats

Flat and XML files are two of the frequently used data file formats. These file formats are both formally structured. However, XML files contain constructs that flat files do not have.

• You can construct a flat file in different ways. Each flat file describes a message that has a corresponding XML schema to match its contents. But there is no corresponding flat file structure for every XML schema.

  You can store each flat file in XML format.

• An XML file is created using custom-defined tags according to XML Document Type Definition (DTD) standards. XML files contain constructs that flat files do not have. An XML is a standard while a flat file is constructed in different ways.

  An XML file cannot be stored in flat file format.

Another important distinction between XML and flat files is that flat files do not contain metadata or information about the data itself. A receiver of a flat file must use a flat file definition to determine how data is organized in a flat file. The definition can include properties such as length of each item, data type such as integer, float, string, or Boolean, and relationships to other data items within the file.