Reflect table changes in models

Rails
1

Hello,

I am adapting an existing system and I want to change some tables. I
want to
turn a column into a reference to a new table. What’s the best way to do
this? I guess migrations but how do I make the new models then?
I am pretty new to rails so if you could provide me with the generator
commands to that would be great. Of course online references are fine
too!

Regards,
Bart

2

Hi Bart,

Bart B. wrote:

how do I make the new models then?

It seems unlikely, for someone undertaking a change to an app’s data
model,
that what you’re looking for is this basic, but just in case… To
generate
a new model for a table:

ruby script\generate model ModelName

Also, don’t forget the Rails convention is that the ModelName is the
singular of the table’s name.

hth,
Bill

3

I am adapting an existing system and I want to change some tables. I want to
turn a column into a reference to a new table. What’s the best way to do
this?
If you have existing models, they will pick up any changes to the
database.

For example, if you a ‘products’ table with an associated ‘Product’
model:

assign price

product.price = 5

Then you decide to change ‘price’ to ‘sale_price’ and generate/run a
migration to do so. You can then just use the new column without
changing your model:

assign price

product.sale_price = 5

Hope that helps and sorry if it’s not quite what you meant :0)

Steve

4

Stephen B. wrote:

product.price = 5

Then you decide to change ‘price’ to ‘sale_price’ and generate/run a
migration to do so. You can then just use the new column without
changing your model:

assign price

product.sale_price = 5

Hope that helps and sorry if it’s not quite what you meant :0)

It’s not really what I meant. I’ll give an example with the product
table. I
currently have price, but say that I want to be a row in another table
pricetag. That row would have columns like tagcolor, currency and value.
(As an example, I don’t need currency conversion!)
So how do I make that conversion to a reference to an external table? If
I
generate the table with migrations it seems to fail…

Regards,
Bart