Database Module

This module contains XQuery Functions to list and open databases, explicitly apply available index structures, or get information on the database structure. All functions are introduced with the db: prefix, which is linked to the http://www.basex.org/db namespace.

db:system

Signatures	db:system() as xs:string
Summary	Lists information on the database system.
Rules	This function returns a simple string with general information on the database system, such as the database path and current database settings.

db:list

Signatures	db:list() as xs:string*
Summary	Lists all databases.
Rules	This function returns a xs:string sequence with the names of all databases.

db:open

Signatures	db:open($name as xs:string) as document-node()
Summary	Retrieves documents from a database.
Rules	This function opens the documents of the database specified by $name. The name of the database may be extended by a collection path.
Examples	The expression db:open("docs") returns all documents from the database named docs. The expression db:open("docs/one") returns all documents from the database named docs in the subpath one.
Errors	BASX0003 is raised if the database is not found.

db:open-pre

Signatures	db:open-pre($name as xs:string, $pre as xs:integer) as node()
Summary	Returns a specific database node.
Rules	This function opens the database specified by $name and returns the node with the pre value specified by $pre.
Examples	The expression db:open-pre("docs", 0) returns the first database node from the database named docs.
Errors	BASX0004 is raised if the specified $pre value does not exist in the database.

db:open-id

Signatures	db:open-id($name as xs:string, $id as xs:integer) as node()
Summary	Returns a specific database node.
Rules	This function opens the database specified by $name and returns the node with the id value specified by $id. In contrast to the pre value, the id will remain valid after update operations.
Errors	BASX0004 is raised if the specified $id does not exist in the database.

db:node-pre

Signatures	db:node-pre($nodes as node()*) as xs:integer*
Summary	Returns the pre values of database nodes.
Rules	This function returns the pre values of all database nodes specified by $nodes. pre values are direct, internal pointers to database nodes, which might be changed by updates.
Examples	The expression db:node-pre(doc("input")) returns 0 if the database input contains a single document.

db:node-id

Signatures	db:node-id($nodes as node()*) as xs:integer*
Summary	Returns the id values of database nodes.
Rules	This function returns the id values of all database nodes specified by $nodes. id values are pointers to database nodes, which are not changed by updates.

db:text

Signatures	db:text($string as item()) as text()*
Summary	Returns results from a text index request.
Rules	This function accesses the text index and returns all text nodes that have $string as string value.
Examples	The expression db:text("QUERY") returns all text nodes of the currently opened database that match the string QUERY. The expression db:open("DB")/db:text("QUERY")/.. returns the parents of all text nodes of the database DB that match the string QUERY.
Errors	BASX0001 is raised if the index is not available. BASX0002 is raised if the context item does not represent a database node.

db:attribute

Signatures	db:attribute($string as item()) as attribute()* db:attribute($string as item(), $name as xs:string) as attribute()*
Summary	Returns results from a attribute index request.
Rules	This function accesses the attribute index and returns all attribute nodes that have $string as string value. If $name is specified, the resulting attribute nodes are filtered by their attribute name.
Examples	The expression db:open("DB")/db:attribute("QUERY", "id")/.. returns the parents of all attribute nodes of the database DB that have QUERY as string value.
Errors	BASX0001 is raised if the index is not available. BASX0002 is raised if the context item does not represent a database node.

db:fulltext

Signatures	db:fulltext($text as xs:string) as text()
Summary	Returns results from a full-text index request.
Rules	This function accesses the full-text index and returns all text nodes that contain the string $text. The index full-text options are used for searching, i.e., if the index terms were stemmed, the search string will be stemmed as well.
Examples	The expression db:fulltext("QUERY") returns all text nodes of the currently opened database that contain the string QUERY.
Errors	BASX0001 is raised if the index is not available. BASX0002 is raised if the context item does not represent a database node.

db:info

Signatures	db:info() as xs:string db:info($type as xs:string) as xs:string
Summary	Returns database information.
Rules	This function returns information on the database that is referenced by the current context item. If $type is specified, the funnction returns information on a database index. It must be one of the values TEXT, ATTRIBUTE, FULLTEXT, PATH, TAG, or ATTNAME.
Errors	BASX0001 is raised if the specified index is not available. BASX0002 is raised if the context item does not represent a database node.