Query Mode

The query mode of the Clients allows you to bind external variables to a query and evaluate the query iteratively. The query() function of the Session instance returns a new query instance.

Usage

The query execution works as follows:

1. Create a new session instance with hostname, port, username, and password.
2. Call query() with your XQuery expression to get a query object.
3. Optionally bind variables to the query with one of the bind() functions.
4. Optionally bind a value to the context item via context().
5. Iterate through the query object with the more() and next() functions.
6. As an alternative, call execute() to get the whole result at a time.
7. info() gives you information on query evaluation.
8. options() returns the query serialization parameters.
9. Don’t forget to close the query with close().

PHP Example

Taken from our repository:

<?php
/* This example shows how queries can be executed iteratively. */
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

• Added: context() function