Is it good practice to have a getter for every property in a class representing a row, or should I investigate another approach?

Question

I have a NoteEntity class that is meant to represent a row in my notes table. An "(data)entity" in my framework strictly means a stored/storable data entry - a database row, if you will. Creating such an object is as straightforward as initializing it with an array returned by mysqli_fetch_array(), which requires me to match the object properties to the column names of my table.

The constructor inherited from the parent DataEntity class:

PHP code

public function __construct($row_array)
{
    foreach ($row_array as $column => $value)
    {
        if (property_exists($this, $column))
        {
            $this->$column = $value;
        }
        else
        {
            trigger_error(get_class($this) . " has no attribute called '$column'.", E_USER_NOTICE);
        }
    }
}

As you can see, all it does is mapping the corresponding columns to their corresponding object properties.

This is fine for me, since the NoteEntity class is defined only once, and thus it is easy to change its internal workings if the table columns would ever change. But this also requires me to use a getter method for each and every property, if I don't want my entire code to depend on the given table's column names.

Question goes as: is it good practice to have a getter for every property, or should I investigate another approach? I'm asking this from a performance perspective, but I'd wish to keep my code as maintainable as possible, as well.

The reason I'm concerned about performance is that if it gets a bit busier, getting the properties quickly becomes:

PHP code

foreach ($notes as $note_entity)
{
    $template->Process(array(
        'note_name' => $note_entity->GetName(),
        'note_ext' => array_pop(explode('.', $note_entity->GetFilename())),
        'subject_id' => $note_entity->GetSubjectID(),
        'subject_name' => $note_entity->GetSubject(),
        'institute_id' => $note_entity->GetInstituteID(),
        'institute_nick' => $note_entity->GetInstitute(),
        // ...
    ));
}

... which might be fine for a few dozen notes, but their count is anticipated to be in even the thousands per request, which adds significant function call overhead. The present version is extremely convenient to use, becase in no part of the code you need to keep the column names in mind.

Possible solutions that I came up with include an approach that returns every, or a subset of every property in an associative array. This has the following minor downsides:

returning only a subset of data creates implicit logical dependencies between NoteEntity and where it is used, if the wanted subset is varying between calling locations,
returning all properties creates an unnecessary flow of data that will never be used,
updating the colum configuration increases the cost of maintainibility, since we need to update the structure of the returned array as well.

score 1 · Accepted Answer · answered Feb 13 '15 at 12:37

I think this is more of a design preference, but there are many advantages of using getters/setters.

Encapsulation and hiding internals are typically good practice. Interoperability is another reason why using getters and setters is a good idea (ie. mocking becomes much easier).

Whether you want to do this for primitives or not is debatable, but typically you don't want to update properties by referencing them directly and especially not externally. So having getters/setters is good way insulate them.

Advantages that you get are much greater than the performance that you're about to lose.

Is it good practice to have a getter for every property in a class representing a row, or should I investigate another approach?

1 Answers1