primary and foregin keys

I have two questions regarding foregin keys.

1. I have two tables in my database. Table number one is called
   "products" and are containing some columns including "prod_number" and
   "date". I want my primary key to be set at the columns like:
   "ALTER TABLE PRODUCTS add CONSTRAINT PK_PROD PRIMARY KEY
   (prod_number,date);"

Now, I have table number two "storage" which contains two columns
"prod_number" and "remain". I want a foregin key to point into the
"product" table like:
"ALTER TABLE STORAGE add CONSTRAINT FK_STORE FOREIGN KEY (prod_number)
REFERENCES PRODUCTS(prod_number);"

This is because I can't have products in store which do not exists. My first question is if it is okay to have a forgin key into
"products" wich does not point out the whole primary key(e.g
prod_number and date). If not, how do I solve the example above?

2. The "storage" table is empty from the begining. I loaded alot of products into the database but have not any of them in storage. It seems impossible to add the foregin key since oracle demands that there must be data in the "storage" table in order to add the foregin key. How do I solve this problem?
I still want to define the constraint even if I don't have any data in my "storage" table yet!

I am running oracle 10g

thanks,

Karolina Received on Thu Dec 23 2004 - 23:54:58 CET