I'm working on a PHP project where some object (class member) may contain different data type. For example :

class Property {
    private $_id;     // (PK)
    private $_ref_id; // the object reference id (FK)
    private $_name;   // the name of the property
    private $_type;   // 'string', 'int', 'float(n,m)', 'datetime', etc.
    private $_data;   // ...

    // ..snip.. public getters/setters
}

Now, I need to perform some persistence on these objects. Some properties may be a text data type, but nothing bigger than what a varchar may hold. Also, later on, I need to be able to perform searches and sorting.

Is it a good practice to use a single database table for this (ie. is there a non negligible performance impact)? If it's "acceptable", then what could be the data type for the data column?