The Drive to Platform-Independent Data Exchange
Applications essentially consist of two parts—functionality described by the code and the data that is manipulated by the code. The in-memory storage and management of data is a key part of any programming language and environment. Within a single application, the programmer is free to decide how the data is stored and represented. Problems only start when the application must exchange data with another application.
One solution is to use an intermediary storage medium, such as a database, and standard tools, such as SQL and JDBC, to gain access to the data in such databases.
But what if the data is to be exchanged directly between two applications, or the applications cannot access the same database? In this case, the data must be encoded in some particular format as it is produced, so that its structure and contents can be understood when it is consumed. This has often resulted in the creation of application-specific data formats, such as binary data files (.dat files) or text-based configuration files (.ini, .rc, .conf, and so on), in which applications store their information.
Similarly, when exchanging information between applications, purpose-specific formats have arisen to address particular needs. Again, these formats can be text-based, such as HTML for encoding how to display the encapsulated data, or binary, such as those used for sending remote procedure calls. In either case, there tends to be a lack of flexibility in the data representation, causing problems when versions change or when data needs to be exchanged between disparate applications, frequently from different vendors.
XML was developed to address these issues. Because XML is written in plain text, and shares similarities with HTML but uses self-describing elements, XML provides a data encoding format that is
Benefits and Characteristics of XML
XML offers a method of putting structured data in a text file. Structured data is data that conforms to a particular format; examples are spreadsheets, address books, configuration parameters, and financial transactions. While being structured, XML is also readable by humans as well as software; this means that you do not need the originating software to access the data.