Class: Simple::SQL::Result::Records

Inherits:
Simple::SQL::Result show all
Defined in:
lib/simple/sql/result/records.rb

Constant Summary collapse

Reflection = 
::Simple::SQL::Reflection
AssociationLoader =

– preload associations ————————————————-

::Simple::SQL::Result::AssociationLoader

Instance Attribute Summary

Attributes inherited from Simple::SQL::Result

#current_page, #total_count, #total_pages

Instance Method Summary collapse

Methods inherited from Simple::SQL::Result

build

Constructor Details

#initialize(records, target_type:, pg_source_oid:) ⇒ Records

:nodoc:



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# File 'lib/simple/sql/result/records.rb', line 9

def initialize(records, target_type:, pg_source_oid:) # :nodoc:
  # expect! records.first => Hash unless records.empty?

  super(records)

  @hash_records   = records
  @target_type    = target_type
  @pg_source_oid  = pg_source_oid
  @associations   = []

  materialize
end

Instance Method Details

#preload(association, as: nil, order_by: nil, limit: nil) ⇒ Object

Preloads an association.

This can now be used as follows:

scope = SQL::Scope.new("SELECT * FROM users")
results = SQL.all scope, into: :struct
results.preload(:organization)

The preload method uses foreign key definitions in the database to figure out which table to load from.

This method is only available if into: was set in the call to SQL.all. It raises an error otherwise.

Parameters:

  • association: the name of the association.

  • as: the target name of the association.

  • order_by: if set describes ordering; see Scope#order_by.

  • limit: if set describes limits; see Scope#order_by.



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# File 'lib/simple/sql/result/records.rb', line 46

def preload(association, as: nil, order_by: nil, limit: nil)
  expect! association => Symbol
  expect! as => [nil, Symbol]

  # resolve oid into table and schema name.
  #
  # [TODO] is this still correct?
  schema, host_table = Reflection.lookup_pg_class @pg_source_oid

  AssociationLoader.preload @hash_records, association,
                            host_table: host_table, schema: schema, as: as,
                            order_by: order_by, limit: limit

  @associations << association

  materialize
end