.NET & XML

Chapter 11. XML and Databases

XML is good for many things. It makes an excellent data interchange format for sharing data between disparate systems, whether through files on disk or through web services on a network. It can be used to share data among homogeneous systems, as in .NET remoting. It can even be used to present data to a person using a text editor for review and modification. In the end, though, the uses of XML are limited by the underlying data storage associated with the XML data; whether it’s in a file or accessed across a network, it usually comes down to some sort of I/O stream.

Relational databases are optimized to store large amounts of data, provide non-sequential access to it, and search and sort the data, all things which XML is not great at. Ultimately, this comes down to the structural difference between a piece of software that is built for the specific purpose of providing this sort of data storage versus XML, a data format which is not optimized for anything in particular.

In addition to the structural differences, relational databases provide several properties that XML by itself cannot. The main properties of a relational database are usually referred to by their acronym ACID:

Atomicity

Any group of actions (called a transaction) taken on the database are done as a group and can only be undone as a group. Any failure of a part of a transaction causes the entire transaction to fail, and roll back the previous actions.

Consistency

Any transaction must ...