Changes

This page is part of the [[Getting Started]] Section.

=Create Databases=

Databases can be created via [[Commands]], via [[XQuery]], in the [[GUI]], and with various [[Developing|APIs]]. If an initial input is specified with a create operation, some time can be saved, as the specified resources will be added to the database in a bulk operation:

* [[Startup#BaseX GUI|GUI]]: Go to ''Database'' → ''New'', press ''Browse…'' to choose an initial file or directory, and press ''OK''.

=Access Resources=

{| class="wikitable"

!Function

!Example

!Description

|{{Function|Database|db:get}}

|{{Code|db:get("db", "path/to/docs")}}

|Returns all documents that are found in the database {{Code|db}} at the (optional) path {{Code|path/to/docs}}.

|<code>[http://www.xqueryfunctions.com/xq/fn_collection.html fn:collection]</code>

|{{Code|collection("db/path/to/docs")}}

|Returns all documents at the location {{Code|path/to/docs}} in the database {{Code|db}}.<br/>If no path is specified after the database, all documents in the database will be returned.<br/>If no argument is specified, all documents of the database will be returned that has been opened in the global context.

|<code>[http://www.xqueryfunctions.com/xq/fn_doc.html fn:doc]</code>

|{{Code|doc("db/path/to/doc.xml")}}

You can access multiple databases in a single query:

for $i in 1 to 100

return db:get('books' || $i)//book/title

If the {{Option|DEFAULTDB}} option is turned on, the path argument of the {{Code|fn:doc}} or {{Code|fn:collection}} functions will first be resolved against the globally opened database.

!Example

!Description

|{{Function|Database|db:name}}

|{{Code|db:name($node)}}

|Returns the name of the database in which the specified {{Code|$node}} is stored.

|{{Function|Database|db:path}}

|{{Code|db:path($node)}}

The {{Code|fn:document-uri}} and {{Code|fn:base-uri}} functions return URIs that can also be reused as arguments for the {{Code|fn:doc}} and {{Code|fn:collection}} functions. As a result, the following example query always returns {{Code|true}}:

every $c in collection('anyDB')

satisfies doc-available(document-uri($c))

If the argument of {{Code|fn:doc}} or {{Code|fn:collection}} does not start with a valid database name, or if the addressed database does not exist, the string is interpreted as URI reference, and the documents found at this location will be returned. Examples:

If the API you use does not support binary output (which is e.g. the case for various [[Clients|Client]] language bindings), you can convert your binary data to its string representation before returning it to the client:

string(db:get-binary('multimedia', 'sample.avi'))

==XQuery Values==

With {{Function|Database|db:get-value}}, XQuery values can be retrieved. In the following example, we assume that an XQuery map {{Code|cities}} was stored in an {{Code|indexes}} database:

let $city-map := db:get-value('indexes', 'cities')

return $city-map?Chile

=Update Resources=

You can also use functions from the [[Database Module]] to add, replace, or delete XML documents:

Function from other modules, such as the [[File Module]], can be utilized to filter the input. With the following code, all files that contain numbers in the filename are selected, and stored as XML. If an input file contains no well-formed XML, it is stored as binary resource, and the error message is stored as a string value:

let $db := 'documents'

for $path in file:list($root)

where matches($path, '\d+')

} catch * {

db:put-binary($db, $root || $path, $path),

}

The error messages can e.g. be analyzed in a second step:

All resources stored in a database can be ''exported'', i.e., written back to disk, e.g., as follows:

* WebDAV: Locate the database directory (or a subdirectory of it) and copy all contents to another location.

=Changelog=

;Version 8.4

;Version 7.2.1

* Updated: {{Code|fn:document-uri}} and {{Code|fn:base-uri}} now return strings that can be reused with {{Code|fn:doc}} or {{Code|fn:collection}} to reopen the original document.