[PHP] PDO fetch_obj - question

[MEM]

Hi there, 
 
I’ve made a fetch_obj and, as stated on some sites, it returns a anonymous
object where the properties will have the name of our columns database. 
 
However, when I do this, I notice that instead of giving me the column names
as they are typed on the DB I get them uppercase. So, when my database field
is “id_dog” to retrieve the property properly I have to search for “ID_DOG”
 
Why is this? Is this a normal behavior?
 
 
Thanks a lot,
Márcio