From BaseX Documentation
This page is part of the Getting Started Section.
In BaseX, a database is a pretty light-weight concept and can be compared to a collection. It contains an arbitrary number of resources, addressed by their unique database path. Resources can either be XML documents or raw files (binaries). Some information on binary data can be found on an extra page.
New databases can be created via commands, in the GUI, or with any of our APIs. If some input is specified along with the create operation, it will be added to the database in a bulk operation:
CREATE DB db /path/to/resourceswill add initial documents to a database
- GUI: Go to Database → New, press Browse to choose an initial file or directory, and press OK
Stored resources and external documents can be accessed in different ways:
Various XQuery functions exist to access XML documents in databases:
|Returns all documents that are found in the database |
|Returns all documents at the location |
If no path is specified after the database, all documents in the database will be returned.
If no argument is specified, all documents of the currently opened database will be returned.
|Returns the document at the location |
An error is raised if the specified addresses does not address exactly one document.
Two more functions are available to extract database information of a node:
|Returns the name of the database in which the specified |
|Returns the path of the database document in which the specified
every $c in collection('anyDB') satisfies doc-available(document-uri($c))
If the argument of
declare option output:method "raw"; db:retrieve('multimedia', 'sample.avi')
Once you have created a database, additional commands exist to modify its contents:
The AUTOFLUSH option can be turned off before bulk operations (i.e. before a large number of new resources is added to the database).
The ADDCACHE option (introduced with Version 7.7) will first cache the input before adding it to the database. This is helpful when the input documents to be added are expected to eat up too much main memory.
The following commands create an empty database, add two resources, explicitly flush data structures to disk, and finally delete all inserted data:
CREATE DB example SET AUTOFLUSH false ADD example.xml SET ADDCACHE true ADD /path/to/xml/documents STORE TO images/ 123.jpg FLUSH DELETE /
You may as well use the BaseX-specific XQuery Database Functions to create, add, replace, and delete XML documents:
let $root := "/path/to/xml/documents/" for $file in file:list($root) return db:add("database", $root || $file)
Last but not least, XML documents can also be added via the GUI and the Database menu.
All resources stored in a database can be exported, i.e., written back to disk. This can be done in several ways: