Is XML a Database?

XML document is a collection of data. In other words it doesn’t make much difference between the other files that store data. A XML in a database format is a self describing, portable, and can describe data in tree or graph structure. XML is a sort of Database Management System (DBMS).

XML provides storage, schemas, query languages, programming interfaces and so on .It lacks in triggers, queries, multi-user access that a real database constitutes. The main advantage of XML is that the data is portable and it allows you to have nested entries.

XML allows you to preserve physical document structure, supports document level transactions and execute queries in an XML query language.

Mapping the XML document schema to the database schema does the transfer of data between XML documents and a database. Mappings between document schemas and database schemas are performed on attributes and text. There are 2 mappings that are generally used to map on XML document schema to the database schema:

1. TABLE BASED MAPPING
2. OBJECT RELATIONAL MAPPING

Native XML databases are designed especially to store XML documents .It is always possible to store data in XML documents in a native XML database. This is done so, when your data is semi-structured. Although, this kind of data can be stored in object oriented and hierarchical databases, it is always better to store it in a native XML database. It enables us to retrieve data much faster than a relational database. One more reason is to store data in a native XML database is to exploit XML specification capabilities, such as executing XML queries.

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What is XML and What Good is XML?

What is XML?

XML stands for eXtensible Markup Language and is a descendant of Standard Generalized Markup Language (SGML), just as HTML is. The most noticeable difference between XML and HTML is the fact that you can define your own tags in XML. That is why XML is considered an extensible language. Because of the freedom of the tags, however, the way in which XML must be written is very strict. Every tag must have a closing tag and all nodes must be ordered properly. If any of these rules are broken, an XML document will simply fail to function. HTML, as many have found, will work even if the document only vaguely looks like an HTML document.

What good is XML?

XML is all about structure. The markup in XML defines what the data represents (i.e. The Catcher in the Rye). HTML, on the other hand, is made for publications. Hence, in HTML, it makes sense to order information by where and how it will appear on the screen. In XML, however, the structure of the information is what's most important. The order of the information is unimportant - it can be displayed in whatever order you want. The important thing is that each piece of data is contained in markup that describes what that data really represents. The structure can be maintained much more easily in XML because of the fact that you can create your own tags.

Think of a book you've read recently. The chapter titles were most likely in bold print. We come to rely on these sorts of conventions to give us a sense of the structure of the document. When you're dealing with a web page, you have to make the structure evident to the reader to help them deal with the information. By using XML, you can easily keep track of information like chapter titles because they will all be contained in markup designating what they are (i.e. Ch. 1 - The Beginning). You can then choose to display that information in whatever way will make it easiest for your reader.

That's what XML is all about: structure.

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What is SOAP and Why?

Soap is a simple XML based protocol to let applications exchange information over HTTP and also a protocol to access web service.

SOAP stands for Simple Object Access Protocol.

Its is important for application development to allow internet communication between programms.

A better way to communicate between applications is over HTTP,because HTTP is supported by all internet browsers and servers.

SOAP provides a way to communicate between applications running on different operating systems, with different technologies and programming languages.

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