Difference between revisions of "Database Module"
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− | This [[Module Library|XQuery Module]] contains functions for processing databases from within XQuery. Existing databases can be opened and listed, its contents can be directly accessed, documents can be added to and removed, etc. All functions are introduced with the {{ | + | This [[Module Library|XQuery Module]] contains functions for processing databases from within XQuery. Existing databases can be opened and listed, its contents can be directly accessed, documents can be added to and removed, etc. All functions are introduced with the {{Code|db:}} prefix, which is linked to the statically declared {{Code|http://basex.org/modules/db}} namespace. |
=Conventions= | =Conventions= | ||
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==Database Nodes== | ==Database Nodes== | ||
− | Many function signatures in this and other modules share {{ | + | Many function signatures in this and other modules share {{Code|$db}} as argument to reference an existing database. The argument may either be a string, denoting the name of the addressed database, or a single node from an already opened database. The following errors may be raised by these functions: |
− | * '''[[#Errors|BXDB0001]]''' is raised if {{ | + | * '''[[#Errors|BXDB0001]]''' is raised if {{Code|$db}} references an XML node that is not stored in a database, or is no database fragment. |
* '''[[#Errors|BXDB0002]]''' is raised if the addressed database cannot be opened. | * '''[[#Errors|BXDB0002]]''' is raised if the addressed database cannot be opened. | ||
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|- | |- | ||
| width='90' | '''Signatures''' | | width='90' | '''Signatures''' | ||
− | |{{ | + | |{{Code|'''db:info'''($db as item()) as element(Database)}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
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|- | |- | ||
| width='90' | '''Signatures''' | | width='90' | '''Signatures''' | ||
− | |{{ | + | |{{Code|'''db:list'''() as xs:string*}}<br/>{{Code|'''db:list'''($db as item()) as xs:string*}}<br/>{{Code|'''db:list'''($db as item(), $path as xs:string) as xs:string*}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
− | |Returns an {{ | + | |Returns an {{Code|xs:string}} sequence with the names of all databases.<br/>If <code>[[#Database Nodes|$db]]</code> is specified, all documents and raw files of the specified database are returned.<br/>The list of resources can be further restricted by the {{Code|$path}} argument. |
|- | |- | ||
| '''Examples''' | | '''Examples''' | ||
| | | | ||
− | * {{ | + | * {{Code|db:list("docs")}} returns the names of all documents from the database named {{Code|docs}}. |
|} | |} | ||
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|- | |- | ||
| width='90' | '''Signatures''' | | width='90' | '''Signatures''' | ||
− | |{{ | + | |{{Code|'''db:list-details'''() as element(database)*}}<br/>{{Code|'''db:list-details'''($db as item()) as element(resource)*}}<br/>{{Code|'''db:list-details'''($db as item(), $path as xs:string) as element(resource)*}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
− | |Returns an {{ | + | |Returns an {{Code|element}} sequence with the names of all databases together with their database path, the number of stored resources and the date of modification.<br/>If <code>[[#Database Nodes|$db]]</code> is specified, all documents and raw files of the specified database together with their content-type, the modification date and the resource type are returned.<br/>The list of resources can be further restricted by the {{Code|$path}} argument. |
|- | |- | ||
| '''Examples''' | | '''Examples''' | ||
| | | | ||
− | * {{ | + | * {{Code|db:list-details("docs")}} returns the names plus additional data of all documents from the database named {{Code|docs}}. |
|} | |} | ||
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|- | |- | ||
| width='90' | '''Signatures''' | | width='90' | '''Signatures''' | ||
− | |{{ | + | |{{Code|'''db:open'''($db as item()) as document-node()*}}<br />{{Code|'''db:open'''($db as item(), $path as xs:string) as document-node()*}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
− | |Returns a sequence with all document nodes contained in the database specified by <code>[[#Database Nodes|$db]]</code>.<br/>The document nodes to be returned can be restricted by the {{ | + | |Returns a sequence with all document nodes contained in the database specified by <code>[[#Database Nodes|$db]]</code>.<br/>The document nodes to be returned can be restricted by the {{Code|$path}} argument. |
|- | |- | ||
| '''Examples''' | | '''Examples''' | ||
| | | | ||
− | * {{ | + | * {{Code|db:open("docs")}} returns all documents from the database named {{Code|docs}}. |
− | * {{ | + | * {{Code|db:open("docs", "one")}} returns all documents from the database named {{Code|docs}} in the subpath {{Code|one}}. |
|} | |} | ||
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|- | |- | ||
| width='90' | '''Signatures''' | | width='90' | '''Signatures''' | ||
− | |{{ | + | |{{Code|'''db:open-id'''($db as item(), $id as xs:integer) as node()}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
− | |Opens the database specified by <code>[[#Database Nodes|$db]]</code> and returns the node with the specified {{ | + | |Opens the database specified by <code>[[#Database Nodes|$db]]</code> and returns the node with the specified {{Code|$id}} value.<br />Each database node has a persistent ''id'', which remains valid after update operations. If no updates are performed, the ''pre'' value can be requested, which provides access to database nodes in constant time. |
|- | |- | ||
| '''Errors''' | | '''Errors''' | ||
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|- | |- | ||
| width='90' | '''Signatures''' | | width='90' | '''Signatures''' | ||
− | |{{ | + | |{{Code|'''db:open-pre'''($db as item(), $pre as xs:integer) as node()}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
− | |Opens the database specified by <code>[[#Database Nodes|$db]]</code> and returns the node with the specified {{ | + | |Opens the database specified by <code>[[#Database Nodes|$db]]</code> and returns the node with the specified {{Code|$pre}} value.<br />The ''pre'' value provides access to a database node in constant time, but it is ''transient'', i.e., it may change when database updates are performed. |
|- | |- | ||
| '''Errors''' | | '''Errors''' | ||
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| '''Examples''' | | '''Examples''' | ||
| | | | ||
− | * {{ | + | * {{Code|db:open-pre("docs", 0)}} returns the first database node from the database named {{Code|docs}}. |
|} | |} | ||
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|- | |- | ||
| width='90' | '''Signatures''' | | width='90' | '''Signatures''' | ||
− | |{{ | + | |{{Code|'''db:system'''() as element(system)}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
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|- | |- | ||
| width='90' | '''Signatures''' | | width='90' | '''Signatures''' | ||
− | |{{ | + | |{{Code|'''db:attribute'''($db as item(), $string as item()) as attribute()*}}<br/>{{Code|'''db:attribute'''($db as item(), $string as item(), $attname as xs:string) as attribute()*}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
− | |Returns all attribute nodes of the database specified by <code>[[#Database Nodes|$db]]</code> that have {{ | + | |Returns all attribute nodes of the database specified by <code>[[#Database Nodes|$db]]</code> that have {{Code|$string}} as string value. If available, the value index is used to speed up evaluation.<br />If {{Code|$attname}} is specified, the resulting attribute nodes are filtered by their attribute name. |
|- | |- | ||
| '''Examples''' | | '''Examples''' | ||
| | | | ||
− | * {{ | + | * {{Code|db:attribute("DB", "QUERY", "id")/..}} returns the parents of all {{Code|id}} attribute nodes of the database {{Code|DB}} that have {{Code|QUERY}} as string value. |
|} | |} | ||
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| width='90' | '''Signatures''' | | width='90' | '''Signatures''' | ||
− | |{{ | + | |{{Code|'''db:attribute-range'''($db as item(), $min as xs:string, $max as xs:string) as text()*}}<br/>{{Code|'''db:attribute-range'''($db as item(), $min as xs:string, $max as xs:string, $attname as xs:string) as attribute()*}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
− | |Returns all attributes of the database specified by <code>[[#Database Nodes|$db]]</code>, the string values of which are larger than or equal to {{ | + | |Returns all attributes of the database specified by <code>[[#Database Nodes|$db]]</code>, the string values of which are larger than or equal to {{Code|$min}} and smaller than or equal to {{Code|$max}}. If available, the value index is used to speed up evaluation. |
|- | |- | ||
| '''Examples''' | | '''Examples''' | ||
| | | | ||
− | * {{ | + | * {{Code|db:attribute-range("DB", "id456", "id473", 'id')}} returns all {{Code|@id}} attributes of the database {{Code|DB}} that have a string value in between {{Code|id456}} and {{Code|id473}}. |
|} | |} | ||
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|- | |- | ||
| width='90' | '''Signatures''' | | width='90' | '''Signatures''' | ||
− | |{{ | + | |{{Code|'''db:fulltext'''($db as item(), $terms as xs:string) as text()*}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
− | |Returns all text nodes from the full-text index of the database specified by <code>[[#Database Nodes|$db]]</code> that contain the text specified as {{ | + | |Returns all text nodes from the full-text index of the database specified by <code>[[#Database Nodes|$db]]</code> that contain the text specified as {{Code|$terms}}.<br/>The options used for building the full-text will also be applied to the search terms. As an example, if the index terms have been stemmed, the search string will be stemmed as well. |
|- | |- | ||
| '''Errors''' | | '''Errors''' | ||
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| '''Examples''' | | '''Examples''' | ||
| | | | ||
− | * {{ | + | * {{Code|db:fulltext("DB", "QUERY")}} returns all text nodes of the database {{Code|DB}} that contain the string {{Code|QUERY}}. |
|} | |} | ||
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|- | |- | ||
| width='90' | '''Signatures''' | | width='90' | '''Signatures''' | ||
− | |{{ | + | |{{Code|'''db:node-id'''($nodes as node()*) as xs:integer*}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
− | |Returns the ''id'' values of all {{ | + | |Returns the ''id'' values of all {{Code|$nodes}} of the database specified by <code>[[#Database Nodes|$db]]</code>.<br/>Each database node has a persistent ''id'', which remains valid after update operations. If no updates are performed, the ''pre'' value can be requested, which provides access to database nodes in constant time. |
|} | |} | ||
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|- | |- | ||
| width='90' | '''Signatures''' | | width='90' | '''Signatures''' | ||
− | |{{ | + | |{{Code|'''db:node-pre'''($nodes as node()*) as xs:integer*}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
− | |Returns the ''pre'' values of all {{ | + | |Returns the ''pre'' values of all {{Code|$nodes}} of the database specified by <code>[[#Database Nodes|$db]]</code>.<br/>The ''pre'' value provides access to a database node in constant time, but it is ''transient'', i.e., it may change when database updates are performed. |
|- | |- | ||
| '''Examples''' | | '''Examples''' | ||
| | | | ||
− | * {{ | + | * {{Code|db:node-pre(doc("input"))}} returns {{Code|0}} if the database {{Code|input}} contains a single document. |
|} | |} | ||
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|- | |- | ||
| width='90' | '''Signatures''' | | width='90' | '''Signatures''' | ||
− | |{{ | + | |{{Code|'''db:retrieve'''($db as item(), $path as xs:string) as xs:base64Binary}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
− | |Returns a binary database resource addressed by <code>[[#Database Nodes|$db]]</code> and {{ | + | |Returns a binary database resource addressed by <code>[[#Database Nodes|$db]]</code> and {{Code|$path}}. |
|- | |- | ||
| '''Errors''' | | '''Errors''' | ||
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| '''Examples''' | | '''Examples''' | ||
| | | | ||
− | * {{ | + | * {{Code|declare option output:method 'raw';<br/>db:retrieve("DB", "music/01.mp3")}} returns the specified audio file as raw data. |
|} | |} | ||
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|- | |- | ||
| width='90' | '''Signatures''' | | width='90' | '''Signatures''' | ||
− | |{{ | + | |{{Code|'''db:text'''($db as item(), $string as item()) as text()*}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
− | |Returns all text nodes of the database specified by <code>[[#Database Nodes|$db]]</code> that have {{ | + | |Returns all text nodes of the database specified by <code>[[#Database Nodes|$db]]</code> that have {{Code|$string}} as their string value. If available, the value index is used to speed up evaluation. |
|- | |- | ||
| '''Examples''' | | '''Examples''' | ||
| | | | ||
− | * {{ | + | * {{Code|db:text("DB", "QUERY")/..}} returns the parents of all text nodes of the database {{Code|DB}} that match the string {{Code|QUERY}}. |
|} | |} | ||
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|- | |- | ||
| width='90' | '''Signatures''' | | width='90' | '''Signatures''' | ||
− | |{{ | + | |{{Code|'''db:text-range'''($db as item(), $min as xs:string, $max as xs:string) as text()*}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
− | |Returns all text nodes of the database specified by <code>[[#Database Nodes|$db]]</code> that are located in between the {{ | + | |Returns all text nodes of the database specified by <code>[[#Database Nodes|$db]]</code> that are located in between the {{Code|$min}} and {{Code|$max}} strings. If available, the value index is used to speed up evaluation. |
|- | |- | ||
| '''Examples''' | | '''Examples''' | ||
| | | | ||
− | * {{ | + | * {{Code|db:text-range("DB", "2000", "2001")}} returns all text nodes of the database {{Code|DB}} that are found in between {{Code|2000}} and {{Code|2001}}. |
|} | |} | ||
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|- | |- | ||
| width='90' | '''Signatures''' | | width='90' | '''Signatures''' | ||
− | |{{ | + | |{{Code|'''db:add'''($db as item(), $input as item()) as empty-sequence()}}<br/>{{Code|'''db:add'''($db as item(), $input as item(), $path as xs:string) as empty-sequence()}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
− | |Adds documents specified by {{ | + | |Adds documents specified by {{Code|$input}} to the database <code>[[#Database Nodes|$db]]</code> and the specified {{Code|$path}}. |
|- | |- | ||
| '''Errors''' | | '''Errors''' | ||
− | |'''[[XQuery Errors#Functions Errors|FODC0002]]''' is raised if {{ | + | |'''[[XQuery Errors#Functions Errors|FODC0002]]''' is raised if {{Code|$input}} is a string representing a path, which cannot be read.<br/>'''[[XQuery Errors#Update Errors|FOUP0001]]''' is raised if {{Code|$input}} is neither string nor a document node. |
|- | |- | ||
| '''Examples''' | | '''Examples''' | ||
| | | | ||
− | * {{ | + | * {{Code|db:add("DB", "/home/dir/doc.xml")}} adds the file {{Code|/home/dir/doc.xml}} to the database {{Code|DB}}. |
− | * {{ | + | * {{Code|db:add("DB", "<a/>", "doc.xml")}} adds a document with content {{Code|<a/>}} to the database {{Code|DB}} under the name {{Code|doc.xml}}. |
− | * {{ | + | * {{Code|db:add("DB", document { <a/> }, "doc.xml")}} adds the document node to the database {{Code|DB}} under the name {{Code|doc.xml}}. |
− | * {{ | + | * {{Code|db:add("DB", "/home/dir", "docs/dir")}} adds all documents in {{Code|/home/dir}} to the database {{Code|DB}} under the path {{Code|docs/dir}}. |
|} | |} | ||
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|- | |- | ||
| width='90' | '''Signatures''' | | width='90' | '''Signatures''' | ||
− | |{{ | + | |{{Code|'''db:delete'''($db as item(), $path as xs:string) as empty-sequence()}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
− | |Deletes document(s), specified by {{ | + | |Deletes document(s), specified by {{Code|$path}}, from the database <code>[[#Database Nodes|$db]]</code>. |
|- | |- | ||
| '''Examples''' | | '''Examples''' | ||
| | | | ||
− | * {{ | + | * {{Code|db:delete("DB", "docs/dir/doc.xml")}} deletes the document {{Code|docs/dir/doc.xml}} in the database {{Code|DB}}. |
− | * {{ | + | * {{Code|db:delete("DB", "docs/dir")}} deletes all documents with paths beginning with {{Code|docs/dir}} in the database {{Code|DB}}. |
|} | |} | ||
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|- | |- | ||
| width='90' | '''Signatures''' | | width='90' | '''Signatures''' | ||
− | |{{ | + | |{{Code|'''db:optimize'''($db as item()) as empty-sequence()}}<br/>{{Code|'''db:optimize'''($db as item(), $all as xs:boolean) as empty-sequence()}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
− | |Optimizes the meta data and indexes of the database <code>[[#Database Nodes|$db]]</code>.<br/>If {{ | + | |Optimizes the meta data and indexes of the database <code>[[#Database Nodes|$db]]</code>.<br/>If {{Code|$all}} is set to {{Code|true()}}, the complete database will be rebuilt. |
|- | |- | ||
| '''Errors''' | | '''Errors''' | ||
− | |'''[[XQuery Errors#BaseX Errors|BASX0014]]''' is raised if an error occurs during optimizing the data structures.<br/>'''[[XQuery Errors#BaseX Errors|BASX0015]]''' is raised if the {{ | + | |'''[[XQuery Errors#BaseX Errors|BASX0014]]''' is raised if an error occurs during optimizing the data structures.<br/>'''[[XQuery Errors#BaseX Errors|BASX0015]]''' is raised if the {{Code|$all}} flag is set to {{Code|true()}}, but the database is an in-memory database.<br/>'''[[XQuery Errors#BaseX Errors|BASX0016]]''' is raised if the database {{Code|$db}} is in use by other user(s). |
|- | |- | ||
| '''Examples''' | | '''Examples''' | ||
| | | | ||
− | * {{ | + | * {{Code|db:optimize("DB")}} optimizes the database structures of the database {{Code|DB}}. |
− | * {{ | + | * {{Code|db:optimize("DB", true())}} optimizes all database structures of the database {{Code|DB}}. |
|} | |} | ||
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|- | |- | ||
| width='90' | '''Signatures''' | | width='90' | '''Signatures''' | ||
− | |{{ | + | |{{Code|'''db:rename'''($db as item(), $path as xs:string, $newpath as xs:string) as empty-sequence()}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
− | |Renames document(s), specified by {{ | + | |Renames document(s), specified by {{Code|$path}} to {{Code|$newpath}} in the database <code>[[#Database Nodes|$db]]</code>. |
|- | |- | ||
| '''Errors''' | | '''Errors''' | ||
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| '''Examples''' | | '''Examples''' | ||
| | | | ||
− | * {{ | + | * {{Code|db:rename("DB", "docs/dir/doc.xml", "docs/dir/newdoc.xml")}} renames the document {{Code|docs/dir/doc.xml}} to {{Code|docs/dir/newdoc.xml}} in the database {{Code|DB}}. |
− | * {{ | + | * {{Code|db:rename("DB", "docs/dir", "docs/newdir")}} renames all documents with paths beginning with {{Code|docs/dir}} to paths beginning with {{Code|docs/newdir}} in the database {{Code|DB}}. |
|} | |} | ||
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|- | |- | ||
| width='90' | '''Signatures''' | | width='90' | '''Signatures''' | ||
− | |{{ | + | |{{Code|'''db:replace'''($db as item(), $path as xs:string, $input as item()) as empty-sequence()}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
− | |Replaces a document, specified by {{ | + | |Replaces a document, specified by {{Code|$path}}, in the database <code>[[#Database Nodes|$db]]</code> with the content of {{Code|$input}}. |
|- | |- | ||
| '''Errors''' | | '''Errors''' | ||
− | |'''[[#Errors|BXDB0006]]''' is raised if {{ | + | |'''[[#Errors|BXDB0006]]''' is raised if {{Code|$path}} is not a single document path.<br/>'''[[XQuery Errors#Functions Errors|FODC0002]]''' is raised if {{Code|$input}} is a string representing a path, which cannot be read.<br/>'''[[XQuery Errors#Update Errors|FOUP0001]]''' is raised if {{Code|$input}} is neither a string nor a document node. |
|- | |- | ||
| '''Examples''' | | '''Examples''' | ||
| | | | ||
− | * {{ | + | * {{Code|db:replace("DB", "docs/dir/doc.xml", "/home/dir/doc.xml")}} replaces the content of the document {{Code|docs/dir/doc.xml}} in the database {{Code|DB}} with the content of the file {{Code|/home/dir/doc.xml}}. |
− | * {{ | + | * {{Code|db:replace("DB", "docs/dir/doc.xml", "<a/>")}} replaces the content of the document {{Code|docs/dir/doc.xml}} in the database {{Code|DB}} with {{Code|<a/>}}. |
− | * {{ | + | * {{Code|db:replace("DB", "docs/dir/doc.xml", document { <a/> })}} replaces the content of the document {{Code|docs/dir/doc.xml}} in the database {{Code|DB}} with the specified document node. |
|} | |} | ||
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|- | |- | ||
| width='90' | '''Signatures''' | | width='90' | '''Signatures''' | ||
− | |{{ | + | |{{Code|'''db:store'''($db as item(), $path as xs:string, $data as item()) as empty-sequence()}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
− | |Stores a binary resource specified by {{ | + | |Stores a binary resource specified by {{Code|$data}} in the database specified by <code>[[#Database Nodes|$db]]</code> and the location specified by {{Code|$path}}. |
|- | |- | ||
| '''Errors''' | | '''Errors''' | ||
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| '''Examples''' | | '''Examples''' | ||
| | | | ||
− | * {{ | + | * {{Code|db:store("DB", "video/sample.mov", file:read-binary('video.mov'))}} stores the addressed video file at the specified location. |
|} | |} | ||
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|- | |- | ||
| width='90' | '''Signatures''' | | width='90' | '''Signatures''' | ||
− | |{{ | + | |{{Code|'''db:output'''($data as item()*) as empty-sequence()}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
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| '''Examples''' | | '''Examples''' | ||
| | | | ||
− | * {{ | + | * {{Code|db:output("Prices have been deleted."), delete node //price}} deletes all {{Code|price}} elements in a database and returns an info message. |
|} | |} | ||
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|- | |- | ||
| width='90' | '''Signatures''' | | width='90' | '''Signatures''' | ||
− | |{{ | + | |{{Code|'''db:exists'''($db as item()) as xs:boolean}}<br/>{{Code|'''db:exists'''($db as item(), $path as xs:string) as xs:boolean}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
− | |Checks if the database specified by <code>[[#Database Nodes|$db]]</code> or the resource specified by {[Mono|$path}} exists. {{ | + | |Checks if the database specified by <code>[[#Database Nodes|$db]]</code> or the resource specified by {[Mono|$path}} exists. {{Code|false}} is returned if a database directory has been addressed. |
|- | |- | ||
| '''Examples''' | | '''Examples''' | ||
| | | | ||
− | * {{ | + | * {{Code|db:exists("DB")}} returns {{Code|true}} if the database {{Code|DB}} exists. |
− | * {{ | + | * {{Code|db:exists("DB", "resource")}} returns {{Code|true}} if {{Code|resource}} is an XML document or a raw file. |
|} | |} | ||
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|- | |- | ||
| width='90' | '''Signatures''' | | width='90' | '''Signatures''' | ||
− | |{{ | + | |{{Code|'''db:is-raw'''($db as item(), $path as xs:string) as xs:boolean}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
− | |Checks if the specified resource in the database <code>[[#Database Nodes|$db]]</code> and the path {{ | + | |Checks if the specified resource in the database <code>[[#Database Nodes|$db]]</code> and the path {{Code|$path}} exists, and if it is a raw file. |
|- | |- | ||
| '''Examples''' | | '''Examples''' | ||
| | | | ||
− | * {{ | + | * {{Code|db:is-raw("DB", "music/01.mp3")}} returns {{Code|true}}. |
|} | |} | ||
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| width='90' | '''Signatures''' | | width='90' | '''Signatures''' | ||
− | |{{ | + | |{{Code|'''db:is-xml'''($db as item(), $path as xs:string) as xs:boolean}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
− | |Checks if the specified resource in the database <code>[[#Database Nodes|$db]]</code> and the path {{ | + | |Checks if the specified resource in the database <code>[[#Database Nodes|$db]]</code> and the path {{Code|$path}} exists, and if it is an XML document. |
|- | |- | ||
| '''Examples''' | | '''Examples''' | ||
| | | | ||
− | * {{ | + | * {{Code|db:is-xml("DB", "dir/doc.xml")}} returns {{Code|true}}. |
|} | |} | ||
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|- | |- | ||
| width='90' | '''Signatures''' | | width='90' | '''Signatures''' | ||
− | |{{ | + | |{{Code|'''db:content-type'''($db as item(), $path as xs:string) as xs:string}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
− | |Retrieves the content type of a resource in the database <code>[[#Database Nodes|$db]]</code> and the path {{ | + | |Retrieves the content type of a resource in the database <code>[[#Database Nodes|$db]]</code> and the path {{Code|$path}}.<br/>The file extension is used to recognize the content-type of a resource stored in the database. Content-type {{Code|application/xml}} will be returned for any XML document stored in the database, regardless of its file name extension. |
|- | |- | ||
| '''Errors''' | | '''Errors''' | ||
Line 424: | Line 424: | ||
| '''Examples''' | | '''Examples''' | ||
| | | | ||
− | * {{ | + | * {{Code|db:content-type("DB", "docs/doc01.pdf")}} returns {{Code|application/pdf}}. |
− | * {{ | + | * {{Code|db:content-type("DB", "docs/doc01.xml")}} returns {{Code|application/xml}}. |
− | * {{ | + | * {{Code|db:content-type("DB", "docs/doc01")}} returns {{Code|application/xml}}, if {{Code|db:is-xml("DB", "docs/doc01")}} returns {{Code|true}}. |
|} | |} | ||
Line 433: | Line 433: | ||
|- | |- | ||
| width='90' | '''Signatures''' | | width='90' | '''Signatures''' | ||
− | |{{ | + | |{{Code|'''db:event'''($name as xs:string, $query as item()) as empty-sequence()}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
− | |Executes a {{ | + | |Executes a {{Code|$query}} and sends the resulting value to all clients watching the [[Events|Event]] with the specified {{Code|$name}}. The query may also perform updates; no event will be sent to the client that fired the event. |
|- | |- | ||
| '''Errors''' | | '''Errors''' | ||
Line 464: | Line 464: | ||
|- | |- | ||
|<code>BXDB0006</code> | |<code>BXDB0006</code> | ||
− | |A database path addressed with {{ | + | |A database path addressed with {{Code|doc()}} contains more than one document. |
|- | |- | ||
|<code>BXDB0007</code> | |<code>BXDB0007</code> |
Revision as of 15:12, 26 May 2012
This XQuery Module contains functions for processing databases from within XQuery. Existing databases can be opened and listed, its contents can be directly accessed, documents can be added to and removed, etc. All functions are introduced with the db:
prefix, which is linked to the statically declared http://basex.org/modules/db
namespace.
Contents
Conventions
All functions in this module are assigned to the http://basex.org/modules/db
namespace, which is statically bound to the db
prefix.
All errors are assigned to the http://basex.org/errors
namespace, which is statically bound to the bxerr
prefix.
Database Nodes
Many function signatures in this and other modules share $db
as argument to reference an existing database. The argument may either be a string, denoting the name of the addressed database, or a single node from an already opened database. The following errors may be raised by these functions:
- BXDB0001 is raised if
$db
references an XML node that is not stored in a database, or is no database fragment. - BXDB0002 is raised if the addressed database cannot be opened.
Last not but least, the argument may also reference a BaseX-specific database fragment. All XML fragments can be converted to database fragments by applying the transform expression on an XML fragment:
copy $c := element hello { 'world' } modify () return db:text($c, 'world')
General Functions
db:info
Signatures | db:info($db as item()) as element(Database)
|
Summary | Returns meta information on the database specified by $db .
|
db:list
Signatures | db:list() as xs:string* db:list($db as item()) as xs:string* db:list($db as item(), $path as xs:string) as xs:string*
|
Summary | Returns an xs:string sequence with the names of all databases.If $db is specified, all documents and raw files of the specified database are returned.The list of resources can be further restricted by the $path argument.
|
Examples |
|
db:list-details
Signatures | db:list-details() as element(database)* db:list-details($db as item()) as element(resource)* db:list-details($db as item(), $path as xs:string) as element(resource)*
|
Summary | Returns an element sequence with the names of all databases together with their database path, the number of stored resources and the date of modification.If $db is specified, all documents and raw files of the specified database together with their content-type, the modification date and the resource type are returned.The list of resources can be further restricted by the $path argument.
|
Examples |
|
db:open
Signatures | db:open($db as item()) as document-node()* db:open($db as item(), $path as xs:string) as document-node()*
|
Summary | Returns a sequence with all document nodes contained in the database specified by $db .The document nodes to be returned can be restricted by the $path argument.
|
Examples |
|
db:open-id
Signatures | db:open-id($db as item(), $id as xs:integer) as node()
|
Summary | Opens the database specified by $db and returns the node with the specified $id value.Each database node has a persistent id, which remains valid after update operations. If no updates are performed, the pre value can be requested, which provides access to database nodes in constant time. |
Errors | BXDB0009 is raised if the specified id value does not exist in the database. |
db:open-pre
Signatures | db:open-pre($db as item(), $pre as xs:integer) as node()
|
Summary | Opens the database specified by $db and returns the node with the specified $pre value.The pre value provides access to a database node in constant time, but it is transient, i.e., it may change when database updates are performed. |
Errors | BXDB0009 is raised if the specified pre value does not exist in the database. |
Examples |
|
db:system
Signatures | db:system() as element(system)
|
Summary | Returns information on the database system, such as the database path and current database settings. |
Read Operations
db:attribute
Signatures | db:attribute($db as item(), $string as item()) as attribute()* db:attribute($db as item(), $string as item(), $attname as xs:string) as attribute()*
|
Summary | Returns all attribute nodes of the database specified by $db that have $string as string value. If available, the value index is used to speed up evaluation.If $attname is specified, the resulting attribute nodes are filtered by their attribute name.
|
Examples |
|
db:attribute-range
Signatures | db:attribute-range($db as item(), $min as xs:string, $max as xs:string) as text()* db:attribute-range($db as item(), $min as xs:string, $max as xs:string, $attname as xs:string) as attribute()*
|
Summary | Returns all attributes of the database specified by $db , the string values of which are larger than or equal to $min and smaller than or equal to $max . If available, the value index is used to speed up evaluation.
|
Examples |
|
db:fulltext
Signatures | db:fulltext($db as item(), $terms as xs:string) as text()*
|
Summary | Returns all text nodes from the full-text index of the database specified by $db that contain the text specified as $terms .The options used for building the full-text will also be applied to the search terms. As an example, if the index terms have been stemmed, the search string will be stemmed as well. |
Errors | BXDB0004 is raised if the full-text index is not available. |
Examples |
|
db:node-id
Signatures | db:node-id($nodes as node()*) as xs:integer*
|
Summary | Returns the id values of all $nodes of the database specified by $db .Each database node has a persistent id, which remains valid after update operations. If no updates are performed, the pre value can be requested, which provides access to database nodes in constant time. |
db:node-pre
Signatures | db:node-pre($nodes as node()*) as xs:integer*
|
Summary | Returns the pre values of all $nodes of the database specified by $db .The pre value provides access to a database node in constant time, but it is transient, i.e., it may change when database updates are performed. |
Examples |
|
db:retrieve
Signatures | db:retrieve($db as item(), $path as xs:string) as xs:base64Binary
|
Summary | Returns a binary database resource addressed by $db and $path .
|
Errors | BXDB0003 is raised if the databse is not persistent (stored on disk). FODC0002 is raised if the addressed resource cannot be retrieved. FODC0007 is raised if the specified path is invalid. |
Examples |
|
db:text
Signatures | db:text($db as item(), $string as item()) as text()*
|
Summary | Returns all text nodes of the database specified by $db that have $string as their string value. If available, the value index is used to speed up evaluation.
|
Examples |
|
db:text-range
Signatures | db:text-range($db as item(), $min as xs:string, $max as xs:string) as text()*
|
Summary | Returns all text nodes of the database specified by $db that are located in between the $min and $max strings. If available, the value index is used to speed up evaluation.
|
Examples |
|
Updates
All functions in this section are treated as updating: they are not immediately executed, but queued on a pending update list, which is processed after the actual query has been evaluated. The XQuery Update page gives more insight into the relevant concepts.
db:add
Signatures | db:add($db as item(), $input as item()) as empty-sequence() db:add($db as item(), $input as item(), $path as xs:string) as empty-sequence()
|
Summary | Adds documents specified by $input to the database $db and the specified $path .
|
Errors | FODC0002 is raised if $input is a string representing a path, which cannot be read.FOUP0001 is raised if $input is neither string nor a document node.
|
Examples |
|
db:delete
Signatures | db:delete($db as item(), $path as xs:string) as empty-sequence()
|
Summary | Deletes document(s), specified by $path , from the database $db .
|
Examples |
|
db:optimize
Signatures | db:optimize($db as item()) as empty-sequence() db:optimize($db as item(), $all as xs:boolean) as empty-sequence()
|
Summary | Optimizes the meta data and indexes of the database $db .If $all is set to true() , the complete database will be rebuilt.
|
Errors | BASX0014 is raised if an error occurs during optimizing the data structures. BASX0015 is raised if the $all flag is set to true() , but the database is an in-memory database.BASX0016 is raised if the database $db is in use by other user(s).
|
Examples |
|
db:rename
Signatures | db:rename($db as item(), $path as xs:string, $newpath as xs:string) as empty-sequence()
|
Summary | Renames document(s), specified by $path to $newpath in the database $db .
|
Errors | BXDB0008 is raised if new document names would be empty. |
Examples |
|
db:replace
Signatures | db:replace($db as item(), $path as xs:string, $input as item()) as empty-sequence()
|
Summary | Replaces a document, specified by $path , in the database $db with the content of $input .
|
Errors | BXDB0006 is raised if $path is not a single document path.FODC0002 is raised if $input is a string representing a path, which cannot be read.FOUP0001 is raised if $input is neither a string nor a document node.
|
Examples |
|
db:store
Signatures | db:store($db as item(), $path as xs:string, $data as item()) as empty-sequence()
|
Summary | Stores a binary resource specified by $data in the database specified by $db and the location specified by $path .
|
Errors | BXDB0003 is raised if the databse is not persistent (stored on disk). FODC0007 is raised if the specified path is invalid. FOUP0002 is raised if the resource cannot be stored at the specified location. |
Examples |
|
db:output
Signatures | db:output($data as item()*) as empty-sequence()
|
Summary | This function can be used to both perform updates and return results in a single query. The argument of the function will be evaluated, and the resulting value will be cached and returned after the updates on the pending update list have been processed. The function can only be used together with updating expressions; if the function is called within a transform expression, its results will be discarded. |
Examples |
|
Helper Functions
db:exists
Signatures | db:exists($db as item()) as xs:boolean db:exists($db as item(), $path as xs:string) as xs:boolean
|
Summary | Checks if the database specified by $db or the resource specified by {[Mono|$path}} exists. false is returned if a database directory has been addressed.
|
Examples |
|
db:is-raw
Signatures | db:is-raw($db as item(), $path as xs:string) as xs:boolean
|
Summary | Checks if the specified resource in the database $db and the path $path exists, and if it is a raw file.
|
Examples |
|
db:is-xml
Signatures | db:is-xml($db as item(), $path as xs:string) as xs:boolean
|
Summary | Checks if the specified resource in the database $db and the path $path exists, and if it is an XML document.
|
Examples |
|
db:content-type
Signatures | db:content-type($db as item(), $path as xs:string) as xs:string
|
Summary | Retrieves the content type of a resource in the database $db and the path $path .The file extension is used to recognize the content-type of a resource stored in the database. Content-type application/xml will be returned for any XML document stored in the database, regardless of its file name extension.
|
Errors | FODC0002 is raised if the addressed resource is not found or cannot be retrieved. |
Examples |
|
db:event
Signatures | db:event($name as xs:string, $query as item()) as empty-sequence()
|
Summary | Executes a $query and sends the resulting value to all clients watching the Event with the specified $name . The query may also perform updates; no event will be sent to the client that fired the event.
|
Errors | BXDB0010 is raised if the specified event is unknown. SEPM0016 is raised if serialization errors occurred while sending the value. |
Errors
Code | Description |
---|---|
BXDB0001
|
A referenced XML node is no database node, i.e. is neither stored in a database nor a database fragment. |
BXDB0002
|
An I/O error occurred while opening a database. |
BXDB0003
|
The addressed database is not persistent (stored on disk). |
BXDB0004
|
The database lacks an index structure required by the called function. |
BXDB0005
|
A query is expected to exclusively return database nodes of a single database. |
BXDB0006
|
A database path addressed with doc() contains more than one document.
|
BXDB0007
|
A database cannot be updated because it is opened by another process. |
BXDB0008
|
Database paths cannot be renamed to empty strings. |
BXDB0009
|
The addressed database id or pre value is out of range. |
BXDB0010
|
The specified event is unknown. |
Changelog
Version 7.2.1
- Added: db:text-range, db:attribute-range, db:output
Version 7.1
- Added: db:list-details, db:content-type
- Updated: db:info, db:system, db:retrieve