rails/activerecord/CHANGELOG.md

• Remove column restrictions for count, let the database raise if the SQL is invalid. The previos behavior was untested and surprising for the user. Fixes #5554.

  Example:

  User.select("name, username").count
  # Before => SELECT count(*) FROM users
  # After => ActiveRecord::StatementInvalid
  
  # you can still use `count(:all)` to perform a query unrelated to the
  # selected columns
  User.select("name, username").count(:all) # => SELECT count(*) FROM users
  

  Yves Senn

• Rails now automatically detects inverse associations. If you do not set the :inverse_of option on the association, then Active Record will guess the inverse association based on heuristics.

  Note that automatic inverse detection only works on has_many, has_one, and belongs_to associations. Extra options on the associations will also prevent the association's inverse from being found automatically.

  The automatic guessing of the inverse association uses a heuristic based on the name of the class, so it may not work for all associations, especially the ones with non-standard names.

  You can turn off the automatic detection of inverse associations by setting the :inverse_of option to false like so:

  class Taggable < ActiveRecord::Base belongs_to :tag, inverse_of: false end

  John Wang

• Fix add_column with array option when using PostgreSQL. Fixes #10432

  Adam Anderson

• Usage of implicit_readonly is being removed. Please use readonlymethod explicitly to mark records asreadonly. Fixes #10615.

  Example:

  user = User.joins(:todos).select("users.*, todos.title as todos_title").readonly(true).first
  user.todos_title = 'clean pet'
  user.save! # will raise error
  

  Yves Senn

• Fix the :primary_key option for has_many associations. Fixes #10693.

  Yves Senn

• Fix bug where tiny types are incorectly coerced as booleand when the length is more than 1.

  Fixes #10620.

  Aaron Peterson

• Also support extensions in PostgreSQL 9.1. This feature has been supported since 9.1.

  kennyj

• Deprecate ConnectionAdapters::SchemaStatements#distinct, as it is no longer used by internals.

  *Ben Woosley#

• Fix pending migrations error when loading schema and ActiveRecord::Base.table_name_prefix is not blank.

  Call assume_migrated_upto_version on connection to prevent it from first being picked up in method_missing.

  In the base class, Migration, method_missing expects the argument to be a table name, and calls proper_table_name on the arguments before sending to connection. If table_name_prefix or table_name_suffix is used, the schema version changes to prefix_version_suffix, breaking rake test:prepare.

  Fixes #10411.

  Kyle Stevens

• Method read_attribute_before_type_cast should accept input as symbol.

  Neeraj Singh

• Confirm a record has not already been destroyed before decrementing counter cache.

  Ben Tucker

• Fixed a bug in ActiveRecord#sanitize_sql_hash_for_conditions in which self.class is an argument to PredicateBuilder#build_from_hash causing PredicateBuilder to call non-existent method Class#reflect_on_association.

  Zach Ohlgren

• While removing index if column option is missing then raise IrreversibleMigration exception.

  Following code should raise IrreversibleMigration. But the code was failing since options is an array and not a hash.

  def change
    change_table :users do |t|
      t.remove_index [:name, :email]
    end
  end
  

  Fix was to check if the options is a Hash before operating on it.

  Fixes #10419.

  Neeraj Singh

• Do not overwrite manually built records during one-to-one nested attribute assignment

  For one-to-one nested associations, if you build the new (in-memory) child object yourself before assignment, then the NestedAttributes module will not overwrite it, e.g.:

  class Member < ActiveRecord::Base
    has_one :avatar
    accepts_nested_attributes_for :avatar
  
    def avatar
      super || build_avatar(width: 200)
    end
  end
  
  member = Member.new
  member.avatar_attributes = {icon: 'sad'}
  member.avatar.width # => 200
  

  Olek Janiszewski

• fixes bug introduced by #3329. Now, when autosaving associations, deletions happen before inserts and saves. This prevents a 'duplicate unique value' database error that would occur if a record being created had the same value on a unique indexed field as that of a record being destroyed.

  Johnny Holton

• Handle aliased attributes in ActiveRecord::Relation.

  When using symbol keys, ActiveRecord will now translate aliased attribute names to the actual column name used in the database:

  With the model

  class Topic
    alias_attribute :heading, :title
  end
  

  The call

  Topic.where(heading: 'The First Topic')
  

  should yield the same result as

  Topic.where(title: 'The First Topic')
  

  This also applies to ActiveRecord::Relation::Calculations calls such as Model.sum(:aliased) and Model.pluck(:aliased).

  This will not work with SQL fragment strings like Model.sum('DISTINCT aliased').

  Godfrey Chan

• Mute psql output when running rake db:schema:load.

  Godfrey Chan

• Trigger a save on has_one association=(associate) when the associate contents have changed.

  Fix #8856.

  Chris Thompson

• Abort a rake task when missing db/structure.sql like db:schema:load task.

  kennyj

• rake:db:test:prepare falls back to original environment after execution.

  Slava Markevich

Please check 4-0-stable for previous changes.