Foreign Keys and Entering Data

rubyonrails-talk
1

Hi,

I'm new to Rails and Database Programming in general. I'm trying to create a site where there is a list of books and the authors. Right now I've got a two tables in my database. One contains information about books, and the other contains the authors. There is a foreign key(author_id) in the books table linking to the id row in the author table. To enter the information there is a form(I haven't made it yet) that asks for the book title, the published date, and the author's first, middle and last name.

Does Rails check for redundancy automatically as far as data is concerned for foreign keys? Let's say my first entry is a book by Stephen King. Now let's say I want to enter another book by Stephen King. Do I write the code checking to see if the author already exists in the DB and then setting the value of that foreign key, or is there something in Ruby/Rails that does this for me? If there is some way that Ruby/Rails does this automatically, what keywords should I be using to find more information?

Thanks.

2

The part on "dynamic finders" in the AR::Base docs may be what your looking for. Look for find_or_create_by and find_or_initialize_by in particular:

<URL:http://api.rubyonrails.org/classes/ActiveRecord/Base.html&gt;

-John

3

Thanks!