I created a scaffold called a book and wanted to create a method for counting how many book entries exist in my database and use that result in the controller of another scaffold called a bulletin board where it will show the total number of books, the total loans and loans to be won
Note: Learning Rails and getting a little syntax.
The Active Record templates have the method #count , which can be used as follows:
Book.count
# SELECT COUNT(*) FROM books
=> 10
You can even apply conditions to the query, like this:
Book.where(status: :active).count
# SELECT COUNT(*) FROM books WHERE books.status = 1
=> 5
To use the view you can interpolate using ERB :
<p>Existem <%= Book.count %> livros disponíveis.
But it is recommended to use logics like this directly in the view, so you can use a instance variable na action:
def index
@book_count = Book.count
end
and the view would look like:
<p>Existem <%= @book_count %> livros disponíveis.