On Oct 3, 5:58 pm, ZeldorBlat <zeldorb...@gmail.com> wrote:
> On Oct 3, 5:47 pm, JamesHoward <James.w.How...@gmail.com> wrote:
>
>
>
> > I have a set of predefined constants with a set of predefined
> > relationships and am looking for a way to link them if possible to
> > ensure data integrity.
>
> > An example would be if I wanted to keep track of programs I have
> > written and I have a table Programs with rows operating system type
> > and programming language. If both operating system type and
> > programming language are foreign keys to reference tables (just tables
> > with a primary key and a name to the element they are referencing) is
> > there a way to ensure data integrity for possible nonsensical pairings
> > such as programming language c# and operating system unix?
>
> > I know that this question isn't specific to MySQL, but I am
> > implementing my database in MySQL and so a solution, if there is a
> > clean one must be implementable in MySQL.
>
> > Thanks in advance,
> > Jim Howard
>
> Sure -- create a fourth table that lists all the valid pairs of
> operating systems and languages. This table would have foreign keys
> to the table of operating systems and the table of programming
> languages. Then, your programs table would have a foreign key to this
> table instead (foreign key constraints can span multiple columns).

Thanks. I am going to give that a shot!

Jim