SQL, Django (models.py) - suggestion, opinion
===

First of all I want to say that I'm complete beginner in SQL. And that's why i'm here =)

I'm doing tables for my website. And before I actually start typing code, I decided to kinda create a template of how it's going to be. Because change it after would take me a lot of time (already had this problem).  And just want to know your opinion, what would you change in order to make it more professional/efficient. 

that's how my tables should relate to each other:
Words in the middle are the Tables Names (Subjects, SubjectContent.... )



    			Subjects

    
    User = ForeignKey(User)
    Class = CharField
    ID = pk
    
    			SubjectContent

    Class = ForeignKey(Subject)
    Homework = ForeignKey(HomeworkContent)
    Class Papers = ForeignKey(ClassPapers)
    Random Papers = ForeignKey(RandomPapers)
    
    
    			FileDescription 
    			*Abstract Class


    Class = ForeignKey(Subject)
    FileLcation = URLField
    FileName = CharField
    FileDescription = TextField
    FileCreationTime = DateField
    
    	class Meta:
    		abstract = True;
    		ordering = ['FileCreationTime']
    
    
    			HomeworkContent (FileDescription)
    
    
    			ClassPapers (FileDescription)
    
    
    			RandomPapers (FileDescription)

