Query Mode
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The query mode of the Clients allows you to bind external variables to a query
and evaluate the query in an iterative manner. The query()
function of the
Session
instance returns a new query instance.
Usage[edit]
The query execution works as follows:
- Create a new session instance with hostname, port, username and password.
- Call
query()
with your XQuery expression to get a query object. - Optionally bind variables to the query with one of the
bind()
functions. - Optionally bind a value to the context item via
context()
. - Iterate through the query object with the
more()
andnext()
functions. - As an alternative, call
execute()
to get the whole result at a time. info()
gives you information on query evaluation.options()
returns the query serialization parameters.- Don't forget to close the query with
close()
.
PHP Example[edit]
Taken from our repository:
<?php
/*
* This example shows how queries can be executed in an iterative manner.
* Documentation: http://basex.org/api
*
* (C) BaseX Team 2005-15, BSD License
*/
include("BaseXClient.php");
try {
// create session
$session = new Session("localhost", 1984, "admin", "...");
try {
// create query instance
$input = 'declare variable $name external; '.
'for $i in 1 to 10 return element { $name } { $i }';
$query = $session->query($input);
// bind variable
$query->bind("$name", "number");
// print result
print $query->execute()."\n";
// close query instance
$query->close();
} catch (Exception $e) {
// print exception
print $e->getMessage();
}
// close session
$session->close();
} catch (Exception $e) {
// print exception
print $e->getMessage();
}
?>
Changelog[edit]
- Version 7.2
- Added:
context()
function