The relationship and interaction between XML and databases
This paper will explore the relationship between XML and databases and the way that they can be leveraged to provide data exchange on the internet. As XML gains popularity as the format for exchanging information via the internet and has become the language of choice for use in database development for Internet use.Introduction XML is a universal data standard and thereby does not need to be translated for use in different database systems. This is very important with large corporate data systems. In companies that have web presence this is a vital concern where some of the data base systems are handled by external companies that use an entirely different database system. Rather than creating a program to make the translation between that databases XML makes the data readable by both database systems by sharing a schema. Is XML a Database
From the beginnings of the information age documents have always contained a wealth of useful information but it was hard to catalogue, this limited its usefulness. XML changed this by allowing the document to be catalogued with the data it contained and allowed targeted searches to be made against the documents. An XML document is a collection of data so in the strictest sense it is a database since it contains data of a sort. It contains several things found in a traditional database management system such as schema, query capabilities and storage of data. So in this sense it is a data base and the XML document can be used to store data. When the need to store large amounts of data arises XML is also a valid choice if the application uses XML as a transport format. For example an e-commerce application that collects order information from a web site and uses XML as the transport format for data. This type of data will have a highly regular structure and can be used by non-XML applications on the back end that gather statistic s on demographics and such for marketing purposes. (Bourret, September, 2005)
Types of XML Databases
When storing XML documents into a database there are two methods of doing so, the first is just map the document schema to the database schema and transfer the data based on that mapping and the second just uses a fixed structure to store any XML document. This presents a scalability problem in that when the system contains a few thousand documents the performance tends to degrade and become a management issue. Synchronization is also a problem between the non-database code and the database. If changes are made to the database structure the XML pointers need to be updated as well and the system is not very portable. The XML mapping style of data storage is used by web sites that map user inputs into XML schema that manages the storage and retrieval of the data as shown in the example Figure 1. This is an effective method when the existing data is in XML format. Using XML to simplify processes
The flexibility of XML has made it the standard for the formatting and sharing of data via the web. XML data is easily transferable across machines and applications and is not constrained by the operating system of the host machine. This ease of translation enables XML to be transformed into non-XML formats for use with databases and their associated applications. An XML database is a database that stores the data fields in XML format. This allows for cross platform transferability and web page presentation. A web application is typically done in three layers the back office code in Java or a similar language that will present the forms on the page and receive the user’s inputs. This code makes is used to present the web page itself and allows a user to enters the data he is making the query for. And the final piece is the database that contains the data and makes it available to the use for queries and processing. (Prohorenko and Prokhorenko, June 2005) The use of XML in...
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