Help with Shopping Cart example from Agile Web Development 2

Rails
1

Hi

I get to about page 103 of the book and get an application error.
Further
investigation reveals the following error in the dev log:
Mysql::Error: #42S22Unknown column ‘id’ in ‘where clause’: UPDATE
sessions
SET data =
‘BAh7BzoJY2FydG86CUNhcnQGOgtAaXRlbXNbBm86DUNhcnRJdGVtBzoOQHF1\nYW50aXR5aQY6DUBwcm9kdWN0bzoMUHJvZHVjdAY6EEBhdHRyaWJ1dGVzewsi\nDmltYWdlX3VybCIWL2ltYWdlcy9yYWlscy5wbmciCnRpdGxlIgdzZCIKcHJp\nY2UiCjIyLjk1IhNkYXRlX2F2YWlsYWJsZSIYMjAwNi0wMS0wNiAxNjoxNzow\nMCIHaWQiBjEiEGRlc2NyaXB0aW9uIghzZGYiCmZsYXNoSUM6J0FjdGlvbkNv\nbnRyb2xsZXI6OkZsYXNoOjpGbGFzaEhhc2h7AAY6CkB1c2VkewA=\n’,
session_id = ‘8766ece0645091e5e6769c2abf77c5c7’, updated_at =
‘2006-05-30 21:29:38’ WHERE id = NULL

If I delete the session entry from the database, the product listing is
displayed, but if I reload the page I get the error again. Any help will
be
very much appreciated.

2

Hmm… the error says that the ‘id’ column can’t be found - that should
have been created when the sessions table was set up.

Have you checked the ‘sessions’ table in the database to see if it has
an ‘id’ column?

Steve

3

Did you get any errors when you run the rake task? I’m not sure why it
wouldn’t work…

Just as a note, the ‘id’ doesn’t appear in the migrations because it’s a
given convention - you wont have to specify it when creating tables
using migrations.

Steve

4

I had trouble running the rake task eg rake db:sessions:create.
The task runs but the table does not get created. So I just went and
created
the database with the three columns from the migration that was
generated eg

  t.column :session_id, :string
  t.column :data, :text
  t.column :updated_at, :datetime

I’ve added an id field and the shopping cart is working. Any idea why
the
rake task did not create the table.

Thanks for you help.

Aneesha

5

Aneesha Bakharia wrote:

I had trouble running the rake task eg rake db:sessions:create.
The task runs but the table does not get created. So I just went and

Are you sure you are rake-ing db:sessions:create and not
db:session:create? I wrote a post about this on my blog[1], and it is my
third most popular post so far - it seems lot of people are running into
this…

bw,
Peter

[1]http://www.rubyrailways.com/dbsessioncreate-problem-in-the-depot-app/