How can I delete some data from DB if there is no primary key?

Using RoR 3.0.7. (ruby 1.9.2)

I have a table books (model Book) with following fields:

book_id - int (not a primary key)

cover_pic - varchar

year - year

I need to delete * rows from DB with books_id = 1 for example.

Have tried:

1) Book.where(:book_id=>1).destroy (nothing)

2) Book.dest开发者_运维知识库roy( Book.where(:book_id=>1) ) (nothing)

3) Book.where(:book_id=>1).each do |obj|

obj.destroy

end

NOTHING .. =(

what am I doing wrong?

thx.

UPD

worked fine delete_all

interesting info: undefined method `eq' for nil:NilClass with rails 3 and ruby enterprise on ubuntu hardy

You can use either of these two:

This will fire all destroy callbacks

Book.destroy_all( :book_id => 1 ) 

This won't

Book.delete_all( :book_id => 1 ) 

Assuming you have some unique index on the table, this works great:

book = Book.first
Book.delete_all(book.attributes)

If you don't have a unique index on the table, the above is dangerous - you could nuke more rows than anticipated. If that is the case, either add a unique index on an existing column (or columns) or else add a PK to the table.