Class: ActiveRecord::InternalMetadata

Inherits:
Base
  • Object
show all
Defined in:
lib/active_record/internal_metadata.rb

Overview

This class is used to create a table that keeps track of values and keys such as which environment migrations were run in.

Constant Summary

Constants included from ConnectionHandling

ConnectionHandling::DEFAULT_ENV, ConnectionHandling::RAILS_ENV

Constants included from Transactions

Transactions::ACTIONS

Constants included from Callbacks

Callbacks::CALLBACKS

Constants included from AttributeMethods

AttributeMethods::AttrNames, AttributeMethods::BLACKLISTED_CLASS_METHODS

Instance Attribute Summary

Attributes included from ConnectionHandling

#connection_specification_name

Class Method Summary collapse

Methods included from ConnectionHandling

#clear_cache!, #connected?, #connection, #connection_config, #connection_pool, #establish_connection, #mysql2_connection, #postgresql_connection, #remove_connection, #retrieve_connection, #sqlite3_connection

Methods included from QueryCache::ClassMethods

#cache, #uncached

Methods included from Querying

#count_by_sql, #find_by_sql

Methods included from Translation

#i18n_scope, #lookup_ancestors

Methods included from DynamicMatchers

#respond_to_missing?

Methods included from Explain

#collecting_queries_for_explain, #exec_explain

Methods included from Enum

#enum, extended, #inherited

Methods included from Delegation::DelegateCache

#inherited, #initialize_relation_delegate_cache, #relation_delegate_class

Methods included from CollectionCacheKey

#collection_cache_key

Methods included from Suppressor

#save, #save!

Methods included from Serialization

#serializable_hash

Methods included from Reflection

add_aggregate_reflection, add_reflection, create

Methods included from NoTouching

applied_to?, apply_to, #no_touching?, #touch, #touch_later

Methods included from TouchLater

#touch, #touch_later

Methods included from Transactions

#add_to_transaction, #before_committed!, #committed!, #destroy, #rollback_active_record_state!, #rolledback!, #save, #save!, #touch, #transaction, #with_transaction_returning_status

Methods included from Aggregations

#initialize_dup, #reload

Methods included from NestedAttributes

#_destroy

Methods included from AutosaveAssociation

#changed_for_autosave?, #destroyed_by_association, #destroyed_by_association=, #mark_for_destruction, #marked_for_destruction?, #reload

Methods included from Associations

#association, #association_cached?, eager_load!, #initialize_dup, #reload

Methods included from Timestamp

#initialize_dup

Methods included from Callbacks

#destroy, #touch

Methods included from AttributeMethods

#[], #[]=, #accessed_fields, #attribute_for_inspect, #attribute_names, #attribute_present?, #attributes, #has_attribute?, #respond_to?

Methods included from Locking::Pessimistic

#lock!, #with_lock

Methods included from Locking::Optimistic

#locking_enabled?

Methods included from Validations

#save, #save!, #valid?

Methods included from Integration

#cache_key, #to_param

Methods included from AttributeAssignment

#attributes=

Methods included from Sanitization

#quoted_id

Methods included from Scoping

#initialize_internals_callback, #populate_with_current_scope_attributes

Methods included from Inheritance

#initialize_dup

Methods included from ModelSchema

derive_join_table_name

Methods included from Persistence

#becomes, #becomes!, #decrement, #decrement!, #delete, #destroy, #destroy!, #destroyed?, #increment, #increment!, #new_record?, #persisted?, #reload, #save, #save!, #toggle, #toggle!, #touch, #update, #update!, #update_attribute, #update_column, #update_columns

Methods included from Core

#<=>, #==, #connection_handler, #encode_with, #freeze, #frozen?, #hash, #init_with, #initialize, #initialize_dup, #inspect, #pretty_print, #readonly!, #readonly?, #slice

Class Method Details

.[](key) ⇒ Object 



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# File 'lib/active_record/internal_metadata.rb', line 21

def [](key)
  where(key: key).pluck(:value).first
end

.[]=(key, value) ⇒ Object 



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# File 'lib/active_record/internal_metadata.rb', line 17

def []=(key, value)
  find_or_initialize_by(key: key).update_attributes!(value: value)
end

.create_table ⇒ Object

Creates an internal metadata table with columns key and value



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# File 'lib/active_record/internal_metadata.rb', line 30

def create_table
  unless table_exists?
    key_options = connection.internal_string_options_for_primary_key

    connection.create_table(table_name, id: false) do |t|
      t.string :key, key_options
      t.string :value
      t.timestamps
    end
  end
end

.primary_key ⇒ Object 



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# File 'lib/active_record/internal_metadata.rb', line 9

def primary_key
  "key"
end

.table_exists? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/internal_metadata.rb', line 25

def table_exists?
  connection.table_exists?(table_name)
end

.table_name ⇒ Object 



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# File 'lib/active_record/internal_metadata.rb', line 13

def table_name
  "#{table_name_prefix}#{ActiveRecord::Base.internal_metadata_table_name}#{table_name_suffix}"
end