How does Magento model distinguish column names in its get/set Model methods?

Question

Let's say I have a Model associated to a table with a column called title. I understand that I can do a $model->setTitle("Hello"); to set a value to this field. I can probably do the same for reading like so ``$model->getTitle();`.

An example would be:

$blogpost = Mage::getModel('weblog/blogpost');
    $blogpost->setTitle('Code Post!');
    $blogpost->setPost('This post was created from code!');
    $blogpost->save();

However, what if the column name was title_name? I could do it with $this->getTitleName() and it worked.

So, I was thinking, if I could use getTitleName() for a column called title_name, then what if I had another column called titleName in the database? How is Magento going to decide between titleName and title_name? How is Magento going to know which column I am referring to?

Answer 1

That's a very specific case so let me clear that up for you.

The magic getters/setters are just wrappers for getData/setData methods.

So in your case:

• title_name can be retrieved by using getData('title_name')
• titleName can be retrieved by using getData('titleName')

However, if you call getTitleName() it will automatically retrieve the title_name column.

Here's why.

Those magic getters/setters are defined in the Varien_Object class as well as two other magic methods has and uns:

public function __call($method, $args)
{
    switch (substr($method, 0, 3)) {
        case 'get' :
            //Varien_Profiler::start('GETTER: '.get_class($this).'::'.$method);
            $key = $this->_underscore(substr($method,3));
            $data = $this->getData($key, isset($args[0]) ? $args[0] : null);
            //Varien_Profiler::stop('GETTER: '.get_class($this).'::'.$method);
            return $data;

        case 'set' :
            //Varien_Profiler::start('SETTER: '.get_class($this).'::'.$method);
            $key = $this->_underscore(substr($method,3));
            $result = $this->setData($key, isset($args[0]) ? $args[0] : null);
            //Varien_Profiler::stop('SETTER: '.get_class($this).'::'.$method);
            return $result;

        case 'uns' :
            //Varien_Profiler::start('UNS: '.get_class($this).'::'.$method);
            $key = $this->_underscore(substr($method,3));
            $result = $this->unsetData($key);
            //Varien_Profiler::stop('UNS: '.get_class($this).'::'.$method);
            return $result;

        case 'has' :
            //Varien_Profiler::start('HAS: '.get_class($this).'::'.$method);
            $key = $this->_underscore(substr($method,3));
            //Varien_Profiler::stop('HAS: '.get_class($this).'::'.$method);
            return isset($this->_data[$key]);
    }
    throw new Varien_Exception("Invalid method ".get_class($this)."::".$method."(".print_r($args,1).")");
}

As you can see the _underscore() method is called on the attribute of the method called.

protected function _underscore($name)
{
    if (isset(self::$_underscoreCache[$name])) {
        return self::$_underscoreCache[$name];
    }
    #Varien_Profiler::start('underscore');
    $result = strtolower(preg_replace('/(.)([A-Z])/', "$1_$2", $name));
    #Varien_Profiler::stop('underscore');
    self::$_underscoreCache[$name] = $result;
    return $result;
}

So in your case, the code that runs would be:

strtolower(preg_replace('/(.)([A-Z])/', "$1_$2", "TitleName"))

Which returns title_name

So getTitleName() will always get you this column and thus the only way to get titleName is by calling getData('titleName')

Answer 2

Convention is to use lower_snake_case for columns and CamelCase in the getters and setters. Best follow these conventions to not run into weird problems.

It's possible to use getData($columName) and setData($columnName, $value) to access arbitrary column names but I highly recommend following the convention.

^{(it's also possible to access title_name with getTitle_name() but don't do everything that is possible just because you can. This is not the intended usage!)}