Question about hashes in views that model a table?

Rails
1

if i have a table called cars with columns called year and type, and i
create a model and do this

@mycars = Cars.find(:all)

in my view i have something like this

for cars in @mycars
do something like print out cars.type

i know that @mycars in a hash where each key is a column name paired
with its corresponding value right?

without the for loop, how can i access the 2nd record directly?
@mycars[0].type = ?

how does the variables in the view know that cars relate to the Cars
table?

is that for loop the same as something like this in c++

for (int i = 0; i < mycars.total; i++)

2

ive also wondered this.

3

baker1 wrote:

i know that @mycars in a hash where each key is a column name paired
with its corresponding value right?

@mycars will be an array of Car objects, each containing an attribute
hash with column name keys.

without the for loop, how can i access the 2nd record directly?
@mycars[0].type = ?

@mycars[1].type = ?, though you probably will not know what car
this is unless you use an :order option in your find that is
some sort of consecutive sequence number.

–
We develop, watch us RoR, in numbers too big to ignore.

4

koloa wrote:

hi mark, thanks for the response

so it is an array of carobjects, where each car object is a hash with
each key being a column name in a table.

A Car object is a proper Ruby object that contains many things.
One of these things is an @attributes instance variable (also
accessible through the “attributes” method), which is a hash with
column name keys. But you usually don’t access this directly.
Rather you use either the attribute access square brackets operator,
or the automatic column-named attribute methods. That is, the
following are equivalent ways to access the “make” column value
of the first Car object found:

     @mycars[0].attributes['make']
     @mycars[0]['make']
     @mycars[0][:make]
     @mycars[0].make

–
We develop, watch us RoR, in numbers too big to ignore.

5

hi mark, thanks for the response

so it is an array of carobjects, where each car object is a hash with
each key being a column name in a table.

Mark Reginald J. wrote:

baker1 wrote:

i know that @mycars in a hash where each key is a column name paired
with its corresponding value right?

@mycars will be an array of Car objects, each containing an attribute
hash with column name keys.

without the for loop, how can i access the 2nd record directly?
@mycars[0].type = ?

@mycars[1].type = ?, though you probably will not know what car
this is unless you use an :order option in your find that is
some sort of consecutive sequence number.

–
We develop, watch us RoR, in numbers too big to ignore.