The array that will contain the parameter names.

An optional single parameter to fetch. When used with no arguments, param returns a list of all known parameter names.

The optional new values to assign to the parameter. Using named parameters, the syntax is:

$query->param(-name=>'parameter',
              -value=>'newvalue'),

or:

$query->param(-name=>'parameter',
              -values=>'newvalue1', 'newvalue2', ...);