Databases

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| valign='top' width='130'|<code>[[Database Module#db:open|db:open()]]</code>
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|<code>[[Database Module#db:open|db:open()]]</code>
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| valign='top' width='220'|{{Mono|db:open("db", "path/to/tocs")}}
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|{{Mono|db:open("db", "path/to/tocs")}}
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|Returns all documents that are found in the specified database at the specified (optional) path.
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|Returns all documents that are found in the database {{Mono|db}} at the (optional) path {{Mono|path/to/docs}}.
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| valign='top'|<code>[http://www.xqueryfunctions.com/xq/fn_collection.html fn:collection()]</code>
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|<code>[http://www.xqueryfunctions.com/xq/fn_collection.html fn:collection()]</code>
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| valign='top' |{{Mono|collection("db/path/to/docs")}}
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|{{Mono|collection("db/path/to/docs")}}
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|Returns all documents at the location {{Mono|path/to/docs}} in the database {{Mono|db}}. All documents in the database are returned if no path is specified.
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|Returns all documents at the location {{Mono|path/to/docs}} in the database {{Mono|db}}.<br/>All documents in the database are returned if no path is specified.
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| valign='top'|<code>[http://www.xqueryfunctions.com/xq/fn_doc.html fn:doc()]</code>
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|<code>[http://www.xqueryfunctions.com/xq/fn_doc.html fn:doc()]</code>
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| valign='top' |{{Mono|doc("db/path/to/doc.xml")}}
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|{{Mono|doc("db/path/to/doc.xml")}}
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|Returns the document at the location {{Mono|path/to/docs}} in the database {{Mono|db}}. An error is raised if the specified addresses does not address exactly one document.
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|Returns the document at the location {{Mono|path/to/docs}} in the database {{Mono|db}}.<br/>An error is raised if the specified addresses does not address exactly one document.
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* {{Mono|doc("http://web.de")}}: retrieves the addressed URI and returns it as a main-memory document node.
* {{Mono|doc("http://web.de")}}: retrieves the addressed URI and returns it as a main-memory document node.
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* {{Mono|collection("/path/to/docs")}}: returns a main-memory collection with all XML documents found in the addressed directory.
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* {{Mono|collection("/path/to/docs")}}: returns a main-memory collection with all XML documents found at the addressed file path.
==Raw Files==
==Raw Files==

Revision as of 22:20, 25 April 2012

This page is part of the Getting Started Section.

In BaseX, a single database contains an arbitrary number of resources, addressed by their unique database path. Since Version 7.0, resources can either be XML documents or raw files (binaries). Sets of XML documents are also called collections. Some information on binary data can be found on an extra page.

Contents

Create/Drop Database

New databases can either be created in the GUI, on command line, or using any of our APIs. XML documents can be specified along with the create operation, which will be added to the database in a bulk operation:

Various parsers can be chosen to influence the database creation, or to convert different formats to XML.

Existing databases can eventually be dropped again:

Database must follow the valid names constraints.

Access Resources

Stored resources and external documents can be accessed in different ways:

XML Documents

Updated with Version 7.2.1:

Various XQuery functions exist to access XML documents in databases and from other locations:

Function Example Description
db:open() db:open("db", "path/to/tocs") Returns all documents that are found in the database db at the (optional) path path/to/docs.
fn:collection() collection("db/path/to/docs") Returns all documents at the location path/to/docs in the database db.
All documents in the database are returned if no path is specified.
fn:doc() doc("db/path/to/doc.xml") Returns the document at the location path/to/docs in the database db.
An error is raised if the specified addresses does not address exactly one document.

The fn:document-uri() and fn:base-uri() functions returns paths that can be reused as arguments for the fn:doc() and fn:collection() functions.

If the argument of fn:doc() or 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:

Raw Files

declare option output:method "raw";
db:retrieve('multimedia', 'sample.avi')

HTTP Services

Update Resources

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 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
ADD ...
STORE TO images/ 123.jpg
FLUSH
DELETE /

You may as well use the BaseX-specific XQuery Database Functions to 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.

Export Data

All resources stored in a database can be exported, i.e., written back to disk. This can be done in several ways:

Changelog

Version 7.2.1

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