Question

Also known as the <<“User has many Databases” question.>>

The environment

My app is modeled like so:

user has_many databases  
database has_many tables  
table has_many rows  
row habtm(+value) columns   

you get the idea!

So instead of modelling a database inside a database,
I would like to have:

• a sqlite3 database that holds the users and
• many sqlite databases for each user

Each user will LCRUD his tables in his databases (similar to phpmyadmin)

The problem

I would like to have thread safe per-request configuration for
database connection and table_name

class Table < ActiveRecord::Base
end

# in some controller
# set the connection to the user-selected database from some DB list
Table.connection = current_user.session.connection
# set the name to the user-selected table from some tables list
Table.table_name = params[:table_name]
@rows = Table.all #display them

EDIT
As you see, the connection is global and shared between threads, but as per my app’s specs, each user has it’s own connection. Now imagine that 2 different users make 2 requests at the same time.

The options?

• I give up ActiveRecord and use bare-bones DB driver
• I give up thread saftey

Answer 1

I believe this is the incantation:
Use Class.new(AR::Base) to dynamically create classes

post_class = Class.new(ActiveRecord::Base)
post_class.connection = set_up_connection()
post_class.table_name = :posts

@posts = post_class.all
puts @posts

# note: post_class will get GC'ed at scope end just like any var, sweet!