Best practice to handle this

rubyonrails-talk
1

Hi!

I have a model which has a field that can have three values only. I store the value in the database as an integer, 0, 1 or 2, but when I display it I want a more appropriate text. And, I want it to be translatable using i18n.

Let’s say that it corresponds to how difficult something is. So, 0 represents “Easy”, 1 represents “Normal” and 2 represents “Hard”.

What I did was first to define it as a hash like this:

DIFFICULTIES = { “Easy” => 0, “Normal” => 1, “Hard” => 2 }

Then I can easily pass this to, for instance, simple_form and it will generate a nice dropdown with the correct values.

But let’s say that I have the value and want to display the text. Then I’d have to iterate over the hash to find which key corresponds to the right value. Right? Not that big of an issue when there are three values as in this example, but there could be more.

How do you normally handle these cases? Is there any “best practice” to handle this in an efficient manner?

Cheers,

Linus

2

Hi!

I have a model which has a field that can have three values only. I store the value in the database as an integer, 0, 1 or 2, but when I display it I want a more appropriate text. And, I want it to be translatable using i18n.

Let's say that it corresponds to how difficult something is. So, 0 represents "Easy", 1 represents "Normal" and 2 represents "Hard". What I did was first to define it as a hash like this: DIFFICULTIES = { "Easy" => 0, "Normal" => 1, "Hard" => 2 } Then I can easily pass this to, for instance, simple_form and it will generate a nice dropdown with the correct values.

But let's say that I have the value and want to display the text. Then I'd have to iterate over the hash to find which key corresponds to the right value. Right? Not that big of an issue when there are three values as in this example, but there could be more.

Use Class: Hash (Ruby 1.9.3) to get the key you want given a value.

I'm thinking that you will only do this if you have a small number of constants that you want to define. If it is a long list, then use the database for that.

3

Hi!

I have a model which has a field that can have three values only. I store the value in the database as an integer, 0, 1 or 2, but when I display it I want a more appropriate text. And, I want it to be translatable using i18n.

Let's say that it corresponds to how difficult something is. So, 0 represents "Easy", 1 represents "Normal" and 2 represents "Hard". What I did was first to define it as a hash like this: DIFFICULTIES = { "Easy" => 0, "Normal" => 1, "Hard" => 2 } Then I can easily pass this to, for instance, simple_form and it will generate a nice dropdown with the correct values.

But let's say that I have the value and want to display the text. Then I'd have to iterate over the hash to find which key corresponds to the right value. Right? Not that big of an issue when there are three values as in this example, but there could be more.

I don't know of any best practice for this, but searching in a hash takes, on average, O(1); so I don't think there's anything to worry about here. Of course, if the hash gets big you might end up with maintainability issues, but that's another story.

4

Not quite sure if I understand this entirely, but you're looking to be able to output the associated text in some place *other* than simple_form? (i.e., when you're displaying the record?)

Seems like it should be straight-forward to map them to values in your locale file. no?

en:   difficulties:     0: Easy     1: Normal     2: Hard

then just invoke:

  t 'difficulties.#{difficulty}'

where you want to display it? And maybe use this to build the Hash for simple_form to begin with?