(PECL maxdb >= 1.0)
maxdb_change_user -- maxdb::change_user — Changes the user of the specified database connection
Estilo por procedimientos
$link
   , string $user
   , string $password
   , string $database
   )Estilo orientado a objetos
$user
   , string $password
   , string $database
   )
   maxdb_change_user() is used to change the user of the specified
   database connection as given by the link parameter and to set the
   current database to that specified by the database parameter.
  
   In order to successfully change users a valid username and
   password parameters must be provided and that user must have
   sufficient permissions to access the desired database. If for any reason authorization
   fails, the current user authentication will remain.
  
Nota:
Using this command will always cause the current database connection to behave as if was a completely new database connection, regardless of if the operation was completed successfully. This reset includes performing a rollback on any active transactions, closing all temporary tables, and unlocking all locked tables.
   Devuelve TRUE en caso de éxito o FALSE en caso de error.
  
Ejemplo #1 Estilo orientado a objetos
<?php
/* connect database test */
$maxdb = new maxdb("localhost", "MONA", "RED", "DEMODB");
/* check connection */
if (maxdb_connect_errno()) {
   printf("Connect failed: %s\n", maxdb_connect_error());
   exit();
}
if ($result = $maxdb->query("SELECT * FROM dual")) {
   $row = $result->fetch_row();
   printf("Result: %s\n", $row[0]);
   $result->free();
}
/* reset all and select a new database */
if (!$maxdb->change_user("DBADMIN", "SECRET", "DEMODB")) {
  printf("Database not running\n");
} else {
  printf("Database running\n");
}
/* close connection */
$maxdb->close();
?>
Ejemplo #2 Estilo por procedimientos
<?php
$link = maxdb_connect("localhost", "MONA", "RED", "DEMODB");
/* check connection */
if (!$link) {
   printf("Connect failed: %s\n", maxdb_connect_error());
   exit();
}
if ($result = maxdb_query($link, "SELECT * FROM dual")) {
   $row = maxdb_fetch_row($result);
   printf("Result: %s\n", $row[0]);
   maxdb_free_result($result);
}
/* reset all and select a new database */
if (!maxdb_change_user($link, "DBADMIN", "SECRET", "DEMODB")) {
  printf("Database not running\n");
} else {
  printf("Database running\n");
}
/* close connection */
maxdb_close($link);
?>
El resultado del ejemplo sería algo similar a:
Result: a Database running