Database Module
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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.
Contents
db:system
Signatures | db:system() as xs:string |
Summary | This function lists information on the database system, including the database path and current database settings. |
db:list
Signatures | db:list() as xs:string* |
Summary | 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 | This function returns a sequence with all document nodes contained in 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 | This function opens the database specified by $name and returns the node with the specified $pre value. |
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 | This function opens the database specified by $name and returns the node with the specified $id value.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 | 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 | 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 | This function accesses the text index and returns all text nodes that have $string as their string value. |
Examples | The expression db:text("QUERY") returns all text nodes of the currently opened database that match the string QUERY .The expression db:open("DB")/db:text("QUERY")/.. returns the parents of all text nodes of the database DB that match the string QUERY . |
Errors | BASX0001 is raised if the index is not available. BASX0002 is raised if the context item does not represent a database node. |
db:attribute
Signatures | db:attribute($string as item()) as attribute()* db:attribute($string as item(), $name as xs:string) as attribute()* |
Summary | This function accesses the attribute index and returns all attribute nodes that have $string as their 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 | 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 | This function returns information on the database that is referenced by the current context item. If $type is specified, the function 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. |