Working with the Database - eXist: A NoSQL Database and Application Development Platform - page 88

*.dbx files. The stored XML is nowhere in sight. What makes things even more con‐
fusing is that stored non-XML files (binaries and queries) can be found in the fs
subdirectory.
So where is the XML? Don't worry. Although you can't find it as a file, the XML
document is stored inside the *.dbx files. eXist ensures that you can access the XML
as though it is still a file and access and query it in an efficient way.
If you're interested in how eXist performs this trick, please refer to Chapter 4 .
Terminology
Let's define some important terminology:
Collections
As noted previously, what is called a directory in a filesystem is called a collection
inside eXist's database. When you use, for instance, the WebDAV interface to
look inside the database, you'll see no difference.
The reason it is called a collection is linked to the definition of the XPath collec
tion function. This function retrieves documents from something it calls a col‐
lection, but the XPath specification does not say exactly what this collection
concept actually is. eXist uses an internal directory-like structure as the basis for
its collections. Read more about this in “Collections” on page 77 and “The collec‐
tion Function” on page 93 .
Resources
What is called a file in a filesystem is called a resource inside eXist's database.
Resources can be anything you usually store in a file: images, CSS files, XQuery
scripts, and, of course, XML documents.
Documents
A resource containing a (well-formed) XML document is called a document .
Properties of Collections and Resources
Anything stored in the database has several properties attached. You can view and
change these properties using, for instance, Java Admin Client tool (see Figure 5-1 ).