Question

I am creating a class for Contact management and I am curious if anyone has any creative ideas to pass in options to make certain columns sortable via ORDER BY in MySQL.

There are 5 columns. ID, Firstname, Lasname, Phone Number, Email.

All of these will need to be sortable Ascending and Descending. The obvious answer would just be to pass in a string for instance “firstname DESC” — but seems a little to open and would like to make the class a little more restrictive.

Any ideas?

Answer 1

The type-safest method would be to use an object which can only hold certain values:

function getUser(UserSortOption $sortOrder) {
    ...
    $sql .= $sortOrder->getField() . $sortOrder->getDirection();
    ...
}

getUser(new UserSortOption(UserSortOption::FIRSTNAME, UserSortOption::DESC));

Gets you all the advantages of strict typing and enumerations. Can be a little bit of an overkill though to have to define, test and include a separate class for every function argument.

Otherwise, you’ll have to check inside the function:

function getUser(array $sort) {
    $sortField = key($sort);
    $sortDirection = current($sort);

    if (!in_array($sortField, array('Firstname', ...))) {
        throw new InvalidArgumentException("Invalid value $sortField for sort parameter");
    }

    ...
}

getUser(array('Firstname' => 'desc'));