has_and_belongs_to_many on different databases

rubyonrails-talk
1

Hi, I'm working with two models that have a "has_and_belongs_to_many" relation. Both models reside on a database that it is not the default one.

A < External   has_and_belongs_to_many: B

B < External   has_and_belongs_to_many: A

Retriving the information for A works perfectly, but when trying to "create" an element on A:

"A.B.create(...)"

ActiveRecord tries to create it on the default database. The solution was doing:

b = B.find(...) A.B << b

But, looking on the sourcecode I've found on the ActiveRecord file "has_and_belongs_to_many_association.rb [25:29]"

      def has_primary_key?         return @has_primary_key unless @has_primary_key.nil?         @has_primary_key = (ActiveRecord::Base.connection.supports_primary_key? &&           ActiveRecord::Base.connection.primary_key(@reflection.options [:join_table]))       end

Shouln't it be something like?

      def has_primary_key?         return @has_primary_key unless @has_primary_key.nil?         @has_primary_key = (@owner.connection.supports_primary_key? &&           @owner.connection.primary_key(@reflection.options [:join_table]))       end

Thank you

2

Hi, I'm working with two models that have a "has_and_belongs_to_many" relation. Both models reside on a database that it is not the default one.

Have you tried using has many through ? with has many through the join table is also a rails model, so you have a place to say that the join table should be in this other database.

Fred

3

I tried it, but doing some tests I found that it allowed to have more than one relation between two elements, a new problem that I don’t know how to solve.

The real problem was with the library file, deleting elements also fails because it tries to use the base connection instead of the ancestor’s one.