Problem understanding scaffolds

Rails
#1

Hey everyone,

I am new to ROR. I have been reading “Begininng Ruby on Rails” by Steven
Holznewr and “Ruby on Rails for Dummies” by Barry B… I have been
going through this a lot slower than I would like, because many of the
examples don’t work and I’ve been trying to glean information from both
books to get them working. My current problem is this:

Following Chapter 9 in “Ruby on Rails for Dummies” we are trying to
build a website for Photos. This website will interface with a mysql
database. I have built out the database, created a model, created a
database table, wrote some code in the migration code to create a column
for filename and description, and created a scaffold.

When I launch the server and view my website for extension photos/new
(creating a new photo in the database), I just see a button titled
“Create”. The book shows a screenshot of two text fields being created,
one for filename and one for description. I’m assuming that I have to
add code to the scaffold to show these forms, is this true? Otherwise
I’m just adding blank entries.

I am currently using
Rad Rails 1.5.0.025739
Ruby 1.8.6
and I believe Rails 2.2

Any suggestions on what I’m missing?

#2

Laim B. wrote:

Hey everyone,

I am new to ROR. I have been reading “Begininng Ruby on Rails” by Steven
Holznewr and “Ruby on Rails for Dummies” by Barry B…

Be careful of learning Rails from books. The Rails framework changes
pretty fast, and book publishers can’t always keep up.

I have been
going through this a lot slower than I would like, because many of the
examples don’t work and I’ve been trying to glean information from both
books to get them working.

Why not try the Rails Guides website instead, or in addition? It’s
excellent and up to date.

My current problem is this:

Following Chapter 9 in “Ruby on Rails for Dummies” we are trying to
build a website for Photos. This website will interface with a mysql
database. I have built out the database, created a model, created a
database table, wrote some code in the migration code to create a column
for filename and description, and created a scaffold.

When I launch the server and view my website for extension photos/new
(creating a new photo in the database), I just see a button titled
“Create”. The book shows a screenshot of two text fields being created,
one for filename and one for description.

You say you wrote the migration; did you remember to run it? Check the
database and make sure that it has the fields you expect. If so,
regenerate the scaffold.

Better yet, just forget that scaffolding exists and find a tutorial that
doesn’t rely on it. :slight_smile:

I’m assuming that I have to
add code to the scaffold to show these forms, is this true?

No. The idea of the scaffold is that it generates a quick-and-dirty set
of views and controller actions based on your database fields. It
sounds like when you generated the scaffold, the generator script didn’t
see any fields in your DB table, so it didn’t put any fields in the
view.

[…]

I am currently using
Rad Rails 1.5.0.025739

Please don’t start learning Rails by using an IDE. The framework is not
well suited to conventional IDEs, and does not really benefit from their
use. Try a full-featured editor instead (I like KomodoEdit and jEdit;
many Rails developers use TextMate).

Ruby 1.8.6
and I believe Rails 2.2

Why start off on an old version of Rails? 2.3.2 is current. Use it
instead.

Best,

Marnen Laibow-Koser
http://www.marnen.org
[email protected]

#3

Laim B. wrote:
[…]

Yea I noticed this and now I’m leery about buying more books. Does Rails
break
compatibility often?

It’s not so much a question of breaking compatibility as of introducing
better ways to do things. Rails is constantly introducing new shortcuts
and abstractions, so if you’re using an old version’s way of doing
things, you may be working too hard.

Do you have a link for the site?

Um, you could have found it in about 5 seconds with Google. I think
it’s http://guides.rubyonrails.org .

The reason that I want to learn Ruby on
Rails is because I have developed a site in HTML/CSS. I want to add a
very simple blog type application that lets a user enter text and create
a blog (I know there are plenty of free blogging programs, but I want to
build something simple for myself). I would also like visitors to leave
simple comments. I figure this is a great project to learn and practice
the fundamentals. I also figure this is a good project to practice using
a database. Will these guides help me in this regard?

Probably. But why don’t you read them and find out?

[…]

When I go into MySQL Administrator, I see the columns in my table.

Great. Are you looking at the right database for the environment you’re
running in (test, dev, or production)? If so, then just use your
version control system (you are using one, right?) to roll back to
before you generated the scaffold, and run script/generate scaffold
again.
[…]

Does a scaffold look at the columns and put in the appropriate field?
For example if it sees you have a column which is a string, will it
display a textbox then?

Yes.
[…]

I originally started off using notepad++ but switched over to using the
ide when I had to jump into the dummies book and follow one of the
tutorials. I’ll try going back to my editor. The thing I liked about the
IDE was that it’s more visual and it’s easier,

That’s why I recommend something like KomodoEdit. It is helpful without
forcing your hand.

but the easiness becomes
a handicap and when something doesn’t work, you have more trouble
figuring out why.

Often true. Some types of automated tools (HTML editors are another
good example) are more helpful when you understand what’s being
automated.

Ruby 1.8.6
and I believe Rails 2.2

Why start off on an old version of Rails? 2.3.2 is current. Use it
instead.

Is there a command I can run to check what version I have?

rails -v will tell you what version will get put into a new app.
script/about will tell you what your app is using.

Best,

Marnen Laibow-Koser
http://www.marnen.org
[email protected]

Thanks!

You’re welcome.

Best,

Marnen Laibow-Koser
http://www.marnen.org
[email protected]

#4

Why start off on an old version of Rails? 2.3.2 is current. Use it
instead.

Is there a command I can run to check what version I have?
ruby script/about
from inside your project root or
gem list rails

hth

#5

Marnen Laibow-Koser wrote:

Laim B. wrote:

Hey everyone,

I am new to ROR. I have been reading “Begininng Ruby on Rails” by Steven
Holznewr and “Ruby on Rails for Dummies” by Barry B…

Be careful of learning Rails from books. The Rails framework changes
pretty fast, and book publishers can’t always keep up.

Yea I noticed this and now I’m leery about buying more books. Does Rails
break
compatibility often?

I have been
going through this a lot slower than I would like, because many of the
examples don’t work and I’ve been trying to glean information from both
books to get them working.

Why not try the Rails Guides website instead, or in addition? It’s
excellent and up to date.

Do you have a link for the site? The reason that I want to learn Ruby on
Rails is because I have developed a site in HTML/CSS. I want to add a
very simple blog type application that lets a user enter text and create
a blog (I know there are plenty of free blogging programs, but I want to
build something simple for myself). I would also like visitors to leave
simple comments. I figure this is a great project to learn and practice
the fundamentals. I also figure this is a good project to practice using
a database. Will these guides help me in this regard?

My current problem is this:

Following Chapter 9 in “Ruby on Rails for Dummies” we are trying to
build a website for Photos. This website will interface with a mysql
database. I have built out the database, created a model, created a
database table, wrote some code in the migration code to create a column
for filename and description, and created a scaffold.

When I launch the server and view my website for extension photos/new
(creating a new photo in the database), I just see a button titled
“Create”. The book shows a screenshot of two text fields being created,
one for filename and one for description.

You say you wrote the migration; did you remember to run it? Check the
database and make sure that it has the fields you expect. If so,
regenerate the scaffold.

When I go into MySQL Administrator, I see the columns in my table.

Better yet, just forget that scaffolding exists and find a tutorial that
doesn’t rely on it. :slight_smile:

I’m assuming that I have to
add code to the scaffold to show these forms, is this true?

No. The idea of the scaffold is that it generates a quick-and-dirty set
of views and controller actions based on your database fields. It
sounds like when you generated the scaffold, the generator script didn’t
see any fields in your DB table, so it didn’t put any fields in the
view.

Does a scaffold look at the columns and put in the appropriate field?
For example if it sees you have a column which is a string, will it
display a textbox then?

[…]

I am currently using
Rad Rails 1.5.0.025739

Please don’t start learning Rails by using an IDE. The framework is not
well suited to conventional IDEs, and does not really benefit from their
use. Try a full-featured editor instead (I like KomodoEdit and jEdit;
many Rails developers use TextMate).

I originally started off using notepad++ but switched over to using the
ide when I had to jump into the dummies book and follow one of the
tutorials. I’ll try going back to my editor. The thing I liked about the
IDE was that it’s more visual and it’s easier, but the easiness becomes
a handicap and when something doesn’t work, you have more trouble
figuring out why.

Ruby 1.8.6
and I believe Rails 2.2

Why start off on an old version of Rails? 2.3.2 is current. Use it
instead.

Is there a command I can run to check what version I have?

Best,

Marnen Laibow-Koser
http://www.marnen.org
[email protected]

Thanks!

#6

Laim,

Scaffold will do it all (in a cookie cutter way), if given the right
arguments.

script/generate scaffold User name:string profile:text
NOTE:--------------------------------^ ----------------^

This single command will create a controller, model, views, and db/
migration for the User model with fields for name and profile.

rake db:migrate
script/server

point your browser at: http://localhost:3000/users and follow the
link to “New user”.

look at the files:

app/controllers/users_controller.rb
app/views/users/…
app/models/user.rb
db/migrate/…create_users.rb