adds a new filtration rule to collection.
$coll->add("$name","$value"); // $name LIKE $value //or $coll->add("$name","$value","comp_oper"); //$name < $value
Parameters:
clears collection (deletes all specified filtration rules).
$coll->clear();
Parameters:
check if there are some rules in collection for the specified field and returns related hash.
$index = $coll->index("name");
Parameters:
Returns:
array of all specified sorting rules.
$name = $coll->rules[0]["name"] $coll->rules[0]["value"]="cde";
Properties: