Adding a FK on a populated table.

[Ahmad Sakhi]

Hello all,

I have the following these two tables, already populated.
The AUTHOR_ID field is a newly added field that I need to
add in my BOOK table, which will serve as a foriegn key to
my AUTHOR table. I have come up with a script to properly
populate this field. However, when I try to add a constraint
as FK on this field, with either cascade, restrict or No action
then, the ALTER doesn't work, and throws an error.

Is it at all possible to define a FK on a field of a table
when the 2 tables are already populated?


BOOK

+----------+------------+-----------+-----------+
| ID	   | TITLE      | VOL       | AUTH_ID   |
+----------+------------+-----------+-----------+
| 001	   | Walk to Re | 01        | 0001      |
+----------+------------+-----------+-----------+
| 002	   | Alfred Jo  | 05        | 0003      |
+----------+------------+-----------+-----------+
| 003	   | The Talk   | 01        | 0004      |
+----------+------------+-----------+-----------+
| 004	   | Kite Runner| 01        | 0001      |
+----------+------------+-----------+-----------+

AUTHOR

+----------+------------+-----------+-----------+
| ID	   | NAME       | BORN      | DIED      |
+----------+------------+-----------+-----------+
| 0001	   | Paul J Ark | 610       | 650       |
+----------+------------+-----------+-----------+
| 0002	   | Kim Lao    | 795       | 850       |
+----------+------------+-----------+-----------+
| 0003	   | Ashrad Al  | 1085      | 1150      |
+----------+------------+-----------+-----------+
| 0004	   | Khaled A B | 1170      | 1220      |
+----------+------------+-----------+-----------+

Thanks.