Getting Valid ENUM Values in ActiveRecord

Rails
1

I know that Rails doesn’t handle database ENUMs. I’d say that 9/10, you
can get away with just using varchar instead. However, there ARE
instances where you need certain functionality that ENUMs provide (ie:
integrity at the datalevel).

I have a working function that will show what enum types are available
for a certain column in a table (I believe this will only work for
MySQL). I would like to take it a step further and abstract this at the
ActiveRecord::Base level. I have the following function, which works if
placed in the individual class level (if there is a more efficient way
to do it let me know):

def get_enum_values(column_name)
self.connection.columns(MyClass.table_name).each { |column|
return column.sql_type.gsub(“enum(’”, “”).gsub("’)",
“”).split("’,’") if column.name == column_name and
column.sql_type[0…4] == “enum”
}
return []
end

The problem is that I have to explicitly call ‘MyClass.table_name’. I
know I can use ‘self.class’ to get the the name of the class that I
need. However, how do I programmatically tell ruby to EXECUTE ‘{The
class who’s name is self.class}.table_name’?

Also, where can I place this new function in my rails app so that now
all ActiveRecord child classes will inherit it?

2

On Sep 9, 2006, at 4:54 PM, Guest wrote:

The problem is that I have to explicitly call ‘MyClass.table_name’. I
know I can use ‘self.class’ to get the the name of the class that I
need. However, how do I programmatically tell ruby to EXECUTE ‘{The
class who’s name is self.class}.table_name’?

I think you can just use:

self.class.table_name

Also, have you look at the Acts As Enumerated plugin. It may solve
the problem you are working on, and even if it doesn’t the code it
will be give you an example of how to extend Active Record.

Aaron