Tammy,
Looks like you need a mapping table. The content repository only stores some default attributes. If you need to store any additional attributes you need to create a table to store them.
If you have a one-to-many relationship between items and attribute values, you'll need a table that looks like this:
create table item_attribute_values (
revision_id integer references cr_revisions,
attribute_value varchar (or whatever is appropriate, possibly boolean)
);
THen you would store one row for each instance of the attribute for each item.
I haven't seen anyplace this is used, but it should work.
Usually there is just one value for each additional attribute.
