Class: OccamsRecord::EagerLoaders::Base

Inherits:

Object

• Object
• OccamsRecord::EagerLoaders::Base

Includes:

Builder

Defined in:

lib/occams-record/eager_loaders/base.rb

Overview

Base class for eagoer loading an association. IMPORTANT eager loaders MUST remain stateless after initialization!

Direct Known Subclasses

BelongsTo, Habtm, HasOne, Through

Instance Attribute Summary

• #name ⇒ String readonly

  Association name.

Instance Method Summary

• #initialize(ref, scope = nil, use: nil, as: nil, optimizer: :select) { ... } ⇒ Base constructor

  ActiveRecord::Relation on which you may call all the normal query hethods (select, where, etc) as well as any scopes you’ve defined on the model.

• #run(rows, query_logger: nil, measurements: nil) ⇒ Object

  Run the query and merge the results into the given rows.

Methods included from Builder

#eager_load, #eager_load_many, #eager_load_one, #nest

Constructor Details

#initialize(ref, scope = nil, use: nil, as: nil, optimizer: :select) { ... } ⇒ Base

ActiveRecord::Relation on which you may call all the normal query hethods (select, where, etc) as well as any scopes you’ve defined on the model.

Parameters:

• ref (ActiveRecord::Association) —

  the ActiveRecord association

• scope (Proc) (defaults to: nil) —

  a scope to apply to the query (optional). It will be passed an

• use (Array(Module)) (defaults to: nil) —

  optional Module to include in the result class (single or array)

• as (Symbol) (defaults to: nil) —

  Load the association usign a different attribute name

• optimizer (Symbol) (defaults to: :select) —

  Only used for ‘through` associations. Options are :none (load all intermediate records) | :select (load all intermediate records but only SELECT the necessary columns)

Yields:

• perform eager loading on this association (optional)

# File 'lib/occams-record/eager_loaders/base.rb', line 21

def initialize(ref, scope = nil, use: nil, as: nil, optimizer: :select, &builder)
  @ref, @scope, @use, @as = ref, scope, use, as
  @model = ref.klass
  @name = (as || ref.name).to_s
  @eager_loaders = EagerLoaders::Context.new(@model)
  @optimizer = optimizer
  instance_exec(&builder) if builder
end

Instance Attribute Details

#name ⇒ String (readonly)

Returns association name.

Returns:

• (String) —

  association name

# File 'lib/occams-record/eager_loaders/base.rb', line 10

def name
  @name
end

Instance Method Details

#run(rows, query_logger: nil, measurements: nil) ⇒ Object

Run the query and merge the results into the given rows.

Parameters:

• rows (Array<OccamsRecord::Results::Row>) —

  Array of rows used to calculate the query.

• query_logger (Array<String>) (defaults to: nil)

# File 'lib/occams-record/eager_loaders/base.rb', line 36

def run(rows, query_logger: nil, measurements: nil)
  query(rows) { |*args|
    assoc_rows = args[0] ? Query.new(args[0], use: @use, eager_loaders: @eager_loaders, query_logger: query_logger, measurements: measurements).run : []
    merge! assoc_rows, rows, *args[1..-1]
  }
  nil
end