Beginning Microsoft SQL Server 2008 ... - S3 Tech Training

The declaration is made with a special tag that begins with a question mark (which indicates that this
tag is a preprocessor directive) and the xml moniker:
The declaration has one required attribute (something that further describes the element) — the version.
In the preceding example, we’ve declared that this is an XML document and also that it is to comply
with version 1.0 (as of this writing, there is also a version 1.1, though you’ll want to stick with 1.0 wherever
possible) of the XML specification.
The declaration can optionally have one additional attribute — this one is called encoding, and it
describes the nature of the character set this XML document utilizes. XML can handle a few different
character sets, most notably UTF-16 and UTF-8. UTF-16 is essentially the Unicode specification, which is
a 16-bit encoding specification that allows for most characters in use in the world today. The default
encoding method is UTF-8, which is backward compatible to the older ASCII specification. A full declaration
would look like this:
Elements
Elements that start with the letters xml are strictly forbidden by the specification — instead, they are
reserved for future expansion of the language.
Elements serve as a piece of glue to hold together descriptive information about something — it honestly
could be anything. Elements define a clear start and end point for your descriptive information.
Usually, elements exist in matched pairs of tags known as an opening tag and a closing tag. Optionally,
however, the opening tag can be self-closing — essentially defining what is known as an empty
element.
The structure for an XML element looks pretty much as HTML tags do. An opening tag will begin with
an opening angle bracket ():
The exception to the rule is if the element is self-closing, in which case the closing angle bracket of the
opening tag is preceded with a forward slash (/):
Closing tags will look exactly like the opening tag (case sensitive), but start with a slash (/) before the
name of the element it’s closing: