storing table names

Hi,

I have a table which needs a geographical category associated with it. However, the geog category can refer to either a country _or_ a continent _or_ a football league (eg Premiership, Serie A, etc). There are two ways to do this that I can think of:

1. have a cont (for continent) field, a coun (for country) field and a leag field, and leave one blank.
2. have a geog field (to store either the word 'country' or the word 'continent' or the word 'league') and a geogid field to point to the relevant field in the table specified in the geog field.

Bearing I mind I need to do this sort of thing in several other places in the DB, which is generally the better solution? The first approach wastes disk space, but will the second approach cause difficulties when specifying foreign key constraints, etc? Would I need to specify three foreign key constraints on the geogid field? Will Oracle let me do that?

TIA,

• Kev