SQL查询可从成分集合中制成的配方

Question

I have a database that has a table of Ingredients I and a table of Recipes R. The two tables have a many-to-many relationship, as one recipes uses many ingredients and one ingredient is used in many recipes. I have a third cross-reference table that uses the cross-reference validation pattern to enforce my many-to-many relationship, and is done using string foreign keys (instead of integers).

Assuming I have a collection of ingredients C outside of my database, how can I query Recipe table R for every recipe that can be made using ONLY the list of ingredients supplied in C?

Other things to consider

1) Speed will (of course) be a concern eventually, but correctness is what I'm stuck on at the moment.

2) The collection of ingredients C might be very large (~100 ingredients).

Any answers or even just pointers in the right direction would be greatly appreciated.

Thanks,

Alec

Answer 1

One way is to write:

select ...
  from R
 where ID not in
        ( select R_ID
            from RI
           where I_ID not in
                  ( select I_ID
                      from C
                  )
        )
;

That is: start with C . Select all recipe–ingredient cross-references where the ingredient is not in C . This gives you the set of all recipes that cannot be made using only ingredients in C . Then, select all recipes that aren't in that set.