Thank you Fred for your answers. It is a big gain for me to learn that we can not use @variable for AR attributes.
On Jan 18, 2:52 pm, Frederick Cheung <[email protected]> wrote: > On Jan 18, 12:16 pm, Rushen Aly <[email protected]> wrote: > > > Ok then, as an example what does the code mean below > > > def encrypt_password > > self.encrypted_password = encrypt(self.password) > > end > > Well it's calling encrypted_password= with the result of encrypting > self.password. In this particular pattern password is normally a > virtual attribute, and the encrypted version of it is stored in the > encrypted_password column > > Fred > > > > > > > > > > > Best Regards > > > Rushen > > > On Jan 18, 1:07 pm, Frederick Cheung <[email protected]> > > wrote: > > > > On Jan 18, 9:34 am, Rushen Aly <[email protected]> wrote: > > > > > Thank you for your reply, > > > > As i understand i always need to use self in spite of @ in a model > > > > Not always, but sometimes you need to in order to resolve an ambiguity > > > eg, if you have a local variable called foo and an accessor method > > > called foo and you write > > > > foo > > > > then ruby needs to decide whether you wanted to call the method foo or > > > just get the local variable. self.foo or foo() tells ruby you wanted > > > to call the acessor method > > > > if you write foo=123, ruby will always assume you wanted to set the > > > local variable foo, so you need to write self.foo = 123 > > > > Fred > > > > > file. I have no information about mass assignment so i am searching > > > > for it... > > > > Best Regards... > > > > Rushen > > > > > On Jan 18, 9:19 am, Frederick Cheung <[email protected]> > > > > wrote: > > > > > > On Jan 18, 6:50 am, Rushen Aly <[email protected]> wrote: > > > > > > > Hi everybody, > > > > > > > I am studying Ruby on Rails Tutorial: Learn Rails by Example at > > > > > > railstutorial.org and currently i am studying chapter 7. There are > > > > > > some issues make me confused. It will be great if you help me on > > > > > > these > > > > > > issues. > > > > > > > 1). We are creating virtual attributes via attr_accessor and making > > > > > > it > > > > > > accessible via attr_accessible. Is this statement correct? I mean if > > > > > > we create a virtual attribute via attr_accessor cant we use it > > > > > > without declaring it with attr_accessible? > > > > > > virtual attributes don't differ from normal attributes when it comes > > > > > to attr_accessible: if you've gone the whitelist approach (ie you've > > > > > used attr_accessible elsewhere), then attributes (virtual or not) are > > > > > protected from mass assignment unless you call attr_accessible on > > > > > them. > > > > > > > 2). What is the difference between self.variable and @variable? Is > > > > > > it > > > > > > something like that we are using self.variable for variables not > > > > > > mentioned in attr_accesible and @variable for variables mentioned in > > > > > > attr_accesible. Is that true? > > > > > > self.variable calls the method called variable (which may or may not > > > > > be backed by an instance variable), whereas @variable access the > > > > > instance variable of that named directly. @variable won't work for an > > > > > active record attribute, since those aren't stored in individual > > > > > instance variables (AR stores a hash of all the database attributes in > > > > > one place( > > > > > > Fred > > > > > > > Best regards... > > > > > > Rushen -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
