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|-
|{{Code|BXCL0006}}
| Function items (including maps and arrays) cannot be returned.
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Please note that the client module should always be used to address independent BaseX server instances. You can create deadlocks if you evaluate a query with a server instance, and if you are addressing the same server instance in your query. See the following example:
<pre classsyntaxhighlight lang="brush:xquery">
(: Retrieve documents from database :)
let $client-id := client:connect('localhost', 1984, 'admin', 'admin')
(: Create database with same name :)
return db:create('conflict', $docs, $docs ! db:path(.))
</presyntaxhighlight>
The read-only query cannot be processed, because the <code>conflict</code> database is currently write-locked by the main query. See [[Transaction Management]] for more background information.
=Conventions=
All functions and errors in this module are assigned to the <code><nowiki>http://basex.org/modules/client</nowiki></code> namespace, which is statically bound to the {{Code|client}} prefix.<br/>All errors are assigned to the <code><nowiki>http://basex.org/errors</nowiki></code> namespace, which is statically bound to the {{Code|bxerr}} prefix.
=Functions=
==client:connect==
{| width='100%'
|-
|-
|'''Errors'''
|{{Error|BXCL0001connect|#Errors}} an error occurs while creating the session (possible reasons: server not available, access denied).<br/>
|}
==client:execute==
{| width='100%'
|-
|-
|'''Errors'''
|{{Error|BXCL0003error|#Errors}} an I/O error occurs while transferring data from or to the server.<br/>{{Error|BXCL0004command|#Errors}} an error occurs while executing a command.
|-
| '''Examples'''
|The following query creates a new database {{Code|TEST}} on a remote BaseX server:
<pre classsyntaxhighlight lang="brush:xquery">
client:connect('basex.server.org', 8080, 'admin', 'admin') !
client:execute(., 'create database TEST')
</presyntaxhighlight>
|}
|-
|'''Errors'''
|{{Error|BXCL0003error|#Errors}} an I/O error occurs while transferring data from or to the server.<br/>{{Error|BXCL0005query|#Errors}} an error occurs while evaluating a query, and if the original error cannot be extracted from the returned error string.<br/>{{Error|BXCL0006function|#Errors}} function items (including maps and arrays) cannot be returned.
|-
| '''Examples'''
|The following query sends a query on a local server instance, binds the integer {{Code|123}} to the variable {{Code|$n}} and returns {{Code|246}}:
<pre classsyntaxhighlight lang="brush:xquery">
let $c := client:connect('localhost', 1984, 'admin', 'admin')
return client:query($c, "declare variable $n external; $n * 2", map { 'n': 123 })
</presyntaxhighlight>
The following query performs a query on a first server, the results of which are passed on to a second server:
<pre classsyntaxhighlight lang="brush:xquery">
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')
</presyntaxhighlight>
|}
==client:close==
{| width='100%'
|-
|-
|'''Errors'''
|{{Error|BXCL0003error|#Errors}} an I/O error occurs while transferring data from or to the server.
|}
|Description
|-
|{{Code|BXCL0001command}}| An error occurred while executing a command.|-|{{Code|connect}}
| An error occurred while creating a new session (possible reasons: server not available, access denied).
|-
|{{Code|BXCL0002error}}| The specified session is unknown, An I/O error occurred while transferring data from or has already been closedto the server.
|-
|{{Code|BXCL0003function}}| An I/O error occurred while transferring data from or to the serverFunction items (including maps and arrays) cannot be returned.
|-
|{{Code|BXCL0004id}}| An error occurred while executing a commandThe id with the specified session is unknown, or has already been closed.
|-
|{{Code|BXCL0005query}}
| 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 9.0
* Updated: error codes updated; errors now use the module namespace
;Version 8.0
