RQL Layer

NoBrainer gives you a lot of sugar so you do not have to write RQL queries yourself. But to really leverage the power of RethinkDB, it is sometimes necessary to go down to the RQL interface. This section describes how to mix RQL statements with NoBrainer.

Running RQL

NoBrainer exposes a run method to run arbitrary RQL command through the query runner middlewares. The following shows an example of the usage of NoBrainer.run

# These four statements are equivalent:
User.count
NoBrainer.run(User.rql_table.count)
NoBrainer.run { User.rql_table.count }
NoBrainer.run { |r| r.table('users').count }

Notice that NoBrainer.run can either take the RQL query as an argument or as a block. When passing a block, you get the r RQL shortcut passed in.

Run Options

NoBrainer.run also accepts options to be passed in the RQL r.run() command:

NoBrainer.run(:profile => true) { |r| r.table('users').count }

Because running queries with certain options is useful (profiling, durability, etc.), NoBrainer provides a method NoBrainer.run_with() which specifies what options to run the RQL queries with. For example:

NoBrainer.run_with(:use_outdated => true) do
  User.each { ... }
end

NoBrainer.run_with() can be nested, and is thread safe.

You may use run_with() to change database as described in the Multi Tenancy section.

Generating RQL from NoBrainer

You can access the RQL table of a model with User.rql_table. Such method would return by default r.table('users'), but can be overriden by the store_in method described in the multi tenancy section.

When using a criteria, you may use criteria.to_rql to retrieve the RQL query that would be performed. For example:

NoBrainer.run { User.where(:name => /john/).to_rql.count }

Instantiating Models

When running raw RQL queries, you may get documents back in an attribute hash format. You may use Model.new_from_db(attrs) to instantiate a model with attributes coming from the database. When using polymorphism, any class in the hierarchy will do.