Difference between revisions of "Client Module"
Jump to navigation
Jump to search
Line 25: | Line 25: | ||
|- | |- | ||
| width='90' | '''Signatures''' | | width='90' | '''Signatures''' | ||
− | |{{Func|client:execute|$id as xs:anyURI, $command as xs:string|xs:string}} | + | |{{Func|client:execute|$id as xs:anyURI, $command as xs:string|xs:string?}} |
|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
− | | This function executes a | + | | This function executes a [[Command]] and returns a result as string, if available. The parameter {{Code|$id}} contains the session id returned by [[Client Module#client:connect|client:connect]]. The {{Code|$command}} represents the database command string, which will be executed by the server. |
|- | |- | ||
|'''Errors''' | |'''Errors''' |
Revision as of 19:56, 23 August 2012
This XQuery Module contains functions to access remote BaseX server instances from XQuery. With this module, you can on the one hand execute database commands and on the other hand evaluate queries, the results of which are returned as XDM sequences.
Contents
Conventions
All functions in this module are assigned to the http://basex.org/modules/client
namespace, which is statically bound to the client
prefix.
All errors are assigned to the http://basex.org/errors
namespace, which is statically bound to the bxerr
prefix.
Functions
client:connect
Signatures | client:connect($host as xs:string, $port as xs:integer, $user as xs:string, $password as xs:string) as xs:anyURI |
Summary | This function establishes a connection to a remote BaseX server, creates a new client session, and returns a session id. The parameter $host is the name of the database server, $port specifies the server port, and $user and $password represent the login data.
|
Errors | BXCL0001 : an error occurs while creating the session (possible reasons: server not available, access denied). |
client:execute
Signatures | client:execute($id as xs:anyURI, $command as xs:string) as xs:string?
|
Summary | This function executes a Command and returns a result as string, if available. The parameter $id contains the session id returned by client:connect. The $command represents the database command string, which will be executed by the server.
|
Errors | BXCL0003 : an I/O error occurs while transferring data from or to the server.BXCL0004 : an error occurs while executing a command.
|
Examples | The following query creates a new database TEST on a remote BaseX server:
client:connect('basex.server.org', 8080, 'admin', 'admin') ! client:execute(., 'create database TEST') |
client:info
Signatures | client:info($id as xs:anyURI) as xs:string
|
Summary | This function returns an information string, created by a previous call of client:execute. $id specifies the session id.
|
client:query
Signatures | client:query($id as xs:anyURI, $query as xs:string) as item()* client:query($id as xs:anyURI, $query as xs:string, $bindings as map(*)) as item()*
|
Summary | Evaluates a query and returns the result as sequence. The parameter $id contains the session id returned by client:connect, and $query represents the query string, which will be evaluated by the server.Variables and the context item can be declared via $bindings . The specified keys must be QNames or strings, the values can be arbitrary items:
|
Errors | BXCL0003 : an I/O error occurs while transferring data from or to the server.BXCL0005 : an error occurs while evaluating a query, and if the original error cannot be extracted from the returned error string.
|
Examples | The following query sends a query on a local server instance, binds the integer 123 to the variable $n and returns 246 :
let $c := client:connect('localhost', 1984, 'admin', 'admin') return client:query($c, "$n * 2", map{ 'n' := 123 }) The following query performs a query on a first server, the results of which are passed on to a second server: let $c1 := client:connect('basex1.server.org', 8080, 'jack', 'C0S19tt2X') let $c2 := client:connect('basex2.server.org', 8080, 'john', '465wFHe26') for $it in client:query($c1, '1 to 10') return client:query($c2, $it || '* 2') |
client:close
Signatures | client:close($id as xs:anyURI) as empty-sequence()
|
Summary | This function closes a client session. $id specifies the session id.At the end of query execution, open sessions will be automatically closed. |
Errors | BXCL0003 : an I/O error occurs while transferring data from or to the server.
|
Errors
Code | Description |
---|---|
BXCL0001
|
An error occurred while creating a new session (possible reasons: server not available, access denied). |
BXCL0002
|
The specified session is unknown, or has already been closed. |
BXCL0003
|
An I/O error occurred while transferring data from or to the server. |
BXCL0004
|
An error occurred while executing a command. |
BXCL0005
|
An error occurred while evaluating a query. Will only be raised if the XQuery error cannot be extracted from the returned error string. |
Changelog
- Version 7.4
- Added: client:info
The module was introduced with Version 7.3.