Database Design Abbreviations

Question

I know that PK stands for primary key, and FK stands for foreign key, but

What does “rK” (in section 3) and “PF” (in sections 3, 4, 6, 7, and 8 mean on this page? http://www.databaseanswers.org/tutorial4_data_modelling/index.htm

And what does "FF" (in the table Customer_Addresses) on this page mean? -Nothing new, so I would just put in one hyperlink, so copy / paste it to go to the page I'm asking about:

databaseanswers.org/tutorial4_db_schema/tutorial_slide_7.htm

Thanks.

Edit: I also understand the concepts of primary keys and foreign keys, but what are these others used for?

Answer 1

This dude has a little annotation system for his charts. It doesn't seem like you need to use them. He defines them here:

http://www.databaseanswers.org/tutorial4_db_schema/tutorial_slide_5.htm

Strange looking, “rK” and “FF” are just rendering problems: they should be FK and PF respectively.

The site is more than a little incompatible in terms of design ... it obviously does not use any data modeling skills when building the site.

Answer 2

PF probably means that the column is both a primary key and a foreign key (i.e. in the 4th normal form situation, i.e. a subtype / supertype)

Answer 3

rk = it looks like the letter F (uppercase) cannot fit into a circle. The circle is smaller than the rest. :)