Active Record Doctor

The active_record_doctor gem maintains compatibility based on the following rules:

1. Any Rails version officially supported by the Rails Core Team is supported by active_record_doctor.
2. Any Ruby version compatible with a supported Rails version is supported.
3. Support is limited to the most recent teeny Ruby versions and patch Rails versions.

Identifies columns that have presence validations in the model but are marked as null: true in the database. Also checks that timestamp columns are NOT NULL.

Usage:

bundle exec rake active_record_doctor:missing_non_null_constraint

Supported configuration options:

• enabled (boolean): Set to false to disable the detector.
• ignore_tables (list): Tables whose columns should not be checked.
• ignore_columns (list): Columns, written as table.column, to ignore.

Identifies boolean columns using presence: true instead of inclusion or exclusion validators. presence cannot be used on booleans because false is considered blank.

Usage:

bundle exec rake active_record_doctor:incorrect_boolean_presence_validation

Supported configuration options:

• enabled (boolean): Set to false to disable the detector.
• ignore_models (list): Models whose validators should not be checked.
• ignore_columns (list): Attributes, written as Model.attribute, to ignore.

Identifies foreign keys that are of a different type than the primary key they reference, which can cause bugs.

Usage:

bundle exec rake active_record_doctor:mismatched_foreign_key_type

Supported configuration options:

• enabled (boolean): Set to false to disable the detector.
• ignore_tables (list): Tables whose foreign keys should not be checked.
• ignore_columns (list): Foreign keys, written as table.column, to ignore.

Identifies tables that lack a primary key, which can cause issues with record lookup and logical replication.

Usage:

bundle exec rake active_record_doctor:table_without_primary_key

Supported configuration options:

• enabled (boolean): Set to false to disable the detector.
• ignore_tables (list): Tables whose primary key existence should not be checked.

If you need to see the supported configuration options and help text for a specific detector, use the :help sub-task. This will display the detector's help text, supported options, their meanings, and whether they are global or local.

bundle exec rake active_record_doctor:extraneous_indexes:help

Identifies mismatches between model-level string length validations and database-level column limits, or missing model validations for existing database limits.

Usage:

bundle exec rake active_record_doctor:incorrect_length_validation

Supported configuration options:

• enabled (boolean): Set to false to disable the detector.
• ignore_models (list): Models whose validators should not be checked.
• ignore_attributes (list): Attributes, written as Model.attribute, to ignore.

Identifies models that reference tables or views that do not exist in the database. This is useful for catching missing migrations.

Compatibility:

• Rails 5+ (any database)
• Rails 4.2 (PostgreSQL only)

Usage:

bundle exec rake active_record_doctor:undefined_table_references

Supported configuration options:

• enabled (boolean): Set to false to disable the detector.
• ignore_models (list): Models whose underlying tables should not be checked.

A multi-column index on column_1, column_2, ..., column_n can replace individual indexes on column_1, column_1, column_2, etc. Use this detector to find redundant indexes.

Workflow:

1. List extraneous indexes:

   bundle exec rake active_record_doctor:extraneous_indexes

2. Manually confirm each index can be safely dropped.
3. Create a migration to drop the indexes.

Note: Unique indexes are never suggested for removal if they could be replaced by a non-unique index, as this would violate uniqueness constraints. Extra indexes on primary keys are also reported.

Supported configuration options:

• enabled (boolean): Set to false to disable the detector.
• ignore_tables (list): Tables whose indexes should never be reported.
• ignore_indexes (list): Specific indexes that should never be reported.

Identifies primary keys using shorter integer types (e.g., INTEGER) instead of BIGINT. This is relevant for projects migrating to or following the Active Record 5.1+ default.

Usage:

bundle exec rake active_record_doctor:short_primary_key_type

Warning: Running migrations to change primary key types on large tables can cause downtime as all rows must be rewritten.

Supported configuration options:

• enabled (boolean): Set to false to disable the detector.
• ignore_tables (list): Tables whose primary keys should not be checked.

Identifies two types of association errors:

1. Using dependent: :delete_all when the dependent models define callbacks (callbacks will be skipped).
2. Using dependent: :destroy when the dependent models have no callbacks (unnecessary overhead of loading models one-by-one).

Usage:

bundle exec rake active_record_doctor:incorrect_dependent_option

Supported configuration options:

• enabled (boolean): Set to false to disable the detector.
• ignore_models (list): Models whose associations should not be checked.
• ignore_associations (list): Associations, written as Model.association, to ignore.

If your project uses Rake but does not use Rails, you can integrate active_record_doctor by adding a new task to your Rakefile using ActiveRecordDoctor::Rake::Task.new.

Important: You must ensure that after running the deps and the setup proc, your Active Record models are loaded and a database connection is established.

require "active_record_doctor"

ActiveRecordDoctor::Rake::Task.new do |task|
  # Add project-specific Rake dependencies that should be run before running
  # active_record_doctor.
  task.deps = []

  # A path to your active_record_doctor configuration file.
  task.config_path = ::Rails.root.join(".active_record_doctor.rb")

  # A Proc called right before running detectors that should ensure your Active
  # Record models are preloaded and a database connection is ready.
  task.setup = -> { ::Rails.application.eager_load! }
end