rails--rails/activerecord/CHANGELOG.md

• Retain explicit selections on the base model after applying includes and joins.

  Resolves #34889.

  Patrick Rebsch

• The database kwarg is deprecated without replacement because it can't be used for sharding and creates an issue if it's used during a request. Applications that need to create new connections should use connects_to instead.

  Eileen M. Uchitelle, John Crepezzi

• Allow attributes to be fetched from Arel node groupings.

  Jeff Emminger, Gannon McGibbon

• A database URL can now contain a querystring value that contains an equal sign. This is needed to support passing PostgresSQL options.

  Joshua Flanagan

• Calling methods like establish_connection with a Hash which is invalid (eg: no adapter) will now raise an error the same way as connections defined in config/database.yml.

  John Crepezzi

• Specifying implicit_order_column now subsorts the records by primary key if available to ensure deterministic results.

  Paweł Urbanek

• where(attr => []) now loads an empty result without making a query.

  John Hawthorn

• Fixed the performance regression for primary_keys introduced MySQL 8.0.

  Hiroyuki Ishii

• Add support for belongs_to to has_many inversing.

  Gannon McGibbon

• Allow length configuration for has_secure_token method. The minimum length is set at 24 characters.

  Before:

  has_secure_token :auth_token
  

  After:

  has_secure_token :default_token             # 24 characters
  has_secure_token :auth_token, length: 36    # 36 characters
  has_secure_token :invalid_token, length: 12 # => ActiveRecord::SecureToken::MinimumLengthError
  

  Bernardo de Araujo

• Deprecate DatabaseConfigurations#to_h. These connection hashes are still available via ActiveRecord::Base.configurations.configs_for.

  Eileen Uchitelle, John Crepezzi

• Add DatabaseConfig#configuration_hash to return database configuration hashes with symbol keys, and use all symbol-key configuration hashes internally. Deprecate DatabaseConfig#config which returns a String-keyed Hash with the same values.

  John Crepezzi, Eileen Uchitelle

• Allow column names to be passed to remove_index positionally along with other options.

  Passing other options can be necessary to make remove_index correctly reversible.

  Before:

  add_index    :reports, :report_id               # => works
  add_index    :reports, :report_id, unique: true # => works
  remove_index :reports, :report_id               # => works
  remove_index :reports, :report_id, unique: true # => ArgumentError
  

  After:

  remove_index :reports, :report_id, unique: true # => works
  

  Eugene Kenny

• Allow bulk ALTER statements to drop and recreate indexes with the same name.

  Eugene Kenny

• insert, insert_all, upsert, and upsert_all now clear the query cache.

  Eugene Kenny

• Call while_preventing_writes directly from connected_to.

  In some cases application authors want to use the database switching middleware and make explicit calls with connected_to. It's possible for an app to turn off writes and not turn them back on by the time we call connected_to(role: :writing).

  This change allows apps to fix this by assuming if a role is writing we want to allow writes, except in the case it's explicitly turned off.

  Eileen M. Uchitelle

• Improve detection of ActiveRecord::StatementTimeout with mysql2 adapter in the edge case when the query is terminated during filesort.

  Kir Shatrov

• Stop trying to read yaml file fixtures when loading Active Record fixtures.

  Gannon McGibbon

• Deprecate .reorder(nil) with .first / .first! taking non-deterministic result.

  To continue taking non-deterministic result, use .take / .take! instead.

  Ryuta Kamizono

• Ensure custom PK types are casted in through reflection queries.

  Gannon McGibbon

• Preserve user supplied joins order as much as possible.

  Fixes #36761, #34328, #24281, #12953.

  Ryuta Kamizono

• Allow matches_regex and does_not_match_regexp on the MySQL Arel visitor.

  James Pearson

• Allow specifying fixtures to be ignored by setting ignore in YAML file's '_fixture' section.

  Tongfei Gao

• Make the DATABASE_URL env variable only affect the primary connection. Add new env variables for multiple databases.

  John Crepezzi, Eileen Uchitelle

• Add a warning for enum elements with 'not_' prefix.

  class Foo
    enum status: [:sent, :not_sent]
  end
  

  Edu Depetris

• Make currency symbols optional for money column type in PostgreSQL.

  Joel Schneider

• Add support for beginless ranges, introduced in Ruby 2.7.

  Josh Goodall

• Add database_exists? method to connection adapters to check if a database exists.

  Guilherme Mansur

• Loading the schema for a model that has no table_name raises a TableNotSpecified error.

  Guilherme Mansur, Eugene Kenny

• PostgreSQL: Fix GROUP BY with ORDER BY virtual count attribute.

  Fixes #36022.

  Ryuta Kamizono

• Make ActiveRecord ConnectionPool.connections method thread-safe.

  Fixes #36465.

  Jeff Doering

• Add support for multiple databases to rails db:abort_if_pending_migrations.

  Mark Lee

• Fix sqlite3 collation parsing when using decimal columns.

  Martin R. Schuster

• Fix invalid schema when primary key column has a comment.

  Fixes #29966.

  Guilherme Goettems Schneider

• Fix table comment also being applied to the primary key column.

  Guilherme Goettems Schneider

• Allow generated create_table migrations to include or skip timestamps.

  Michael Duchemin

Please check 6-0-stable for previous changes.