require "monitor" module ActiveRecord module ModelSchema extend ActiveSupport::Concern ## # :singleton-method: primary_key_prefix_type # :call-seq: primary_key_prefix_type # # The prefix type that will be prepended to every primary key column name. # The options are +:table_name+ and +:table_name_with_underscore+. If the first is specified, # the Product class will look for "productid" instead of "id" as the primary column. If the # latter is specified, the Product class will look for "product_id" instead of "id". Remember # that this is a global setting for all Active Records. ## # :singleton-method: primary_key_prefix_type= # :call-seq: primary_key_prefix_type=(prefix_type) # # Sets the prefix type that will be prepended to every primary key column name. # The options are +:table_name+ and +:table_name_with_underscore+. If the first is specified, # the Product class will look for "productid" instead of "id" as the primary column. If the # latter is specified, the Product class will look for "product_id" instead of "id". Remember # that this is a global setting for all Active Records. ## # :singleton-method: table_name_prefix # :call-seq: table_name_prefix # # The prefix string to prepend to every table name. ## # :singleton-method: table_name_prefix= # :call-seq: table_name_prefix=(prefix) # # Sets the prefix string to prepend to every table name. So if set to "basecamp_", all table # names will be named like "basecamp_projects", "basecamp_people", etc. This is a convenient # way of creating a namespace for tables in a shared database. By default, the prefix is the # empty string. # # If you are organising your models within modules you can add a prefix to the models within # a namespace by defining a singleton method in the parent module called table_name_prefix which # returns your chosen prefix. ## # :singleton-method: table_name_suffix # :call-seq: table_name_suffix # # The suffix string to append to every table name. ## # :singleton-method: table_name_suffix= # :call-seq: table_name_suffix=(suffix) # # Works like +table_name_prefix=+, but appends instead of prepends (set to "_basecamp" gives "projects_basecamp", # "people_basecamp"). By default, the suffix is the empty string. # # If you are organising your models within modules, you can add a suffix to the models within # a namespace by defining a singleton method in the parent module called table_name_suffix which # returns your chosen suffix. ## # :singleton-method: schema_migrations_table_name # :call-seq: schema_migrations_table_name # # The name of the schema migrations table. By default, the value is "schema_migrations". ## # :singleton-method: schema_migrations_table_name= # :call-seq: schema_migrations_table_name=(table_name) # # Sets the name of the schema migrations table. ## # :singleton-method: internal_metadata_table_name # :call-seq: internal_metadata_table_name # # The name of the internal metadata table. By default, the value is "ar_internal_metadata". ## # :singleton-method: internal_metadata_table_name= # :call-seq: internal_metadata_table_name=(table_name) # # Sets the name of the internal metadata table. ## # :singleton-method: protected_environments # :call-seq: protected_environments # # The array of names of environments where destructive actions should be prohibited. By default, # the value is ["production"]. ## # :singleton-method: protected_environments= # :call-seq: protected_environments=(environments) # # Sets an array of names of environments where destructive actions should be prohibited. ## # :singleton-method: pluralize_table_names # :call-seq: pluralize_table_names # # Indicates whether table names should be the pluralized versions of the corresponding class names. # If true, the default table name for a Product class will be "products". If false, it would just be "product". # See table_name for the full rules on table/class naming. This is true, by default. ## # :singleton-method: pluralize_table_names= # :call-seq: pluralize_table_names=(value) # # Set whether table names should be the pluralized versions of the corresponding class names. # If true, the default table name for a Product class will be "products". If false, it would just be "product". # See table_name for the full rules on table/class naming. This is true, by default. ## # :singleton-method: ignored_columns # :call-seq: ignored_columns # # The list of columns names the model should ignore. Ignored columns won't have attribute # accessors defined, and won't be referenced in SQL queries. ## # :singleton-method: ignored_columns= # :call-seq: ignored_columns=(columns) # # Sets the columns names the model should ignore. Ignored columns won't have attribute # accessors defined, and won't be referenced in SQL queries. included do mattr_accessor :primary_key_prefix_type, instance_writer: false class_attribute :table_name_prefix, instance_writer: false, default: "" class_attribute :table_name_suffix, instance_writer: false, default: "" class_attribute :schema_migrations_table_name, instance_accessor: false, default: "schema_migrations" class_attribute :internal_metadata_table_name, instance_accessor: false, default: "ar_internal_metadata" class_attribute :protected_environments, instance_accessor: false, default: [ "production" ] class_attribute :pluralize_table_names, instance_writer: false, default: true class_attribute :ignored_columns, instance_accessor: false, default: [].freeze self.inheritance_column = "type" delegate :type_for_attribute, to: :class initialize_load_schema_monitor end # Derives the join table name for +first_table+ and +second_table+. The # table names appear in alphabetical order. A common prefix is removed # (useful for namespaced models like Music::Artist and Music::Record): # # artists, records => artists_records # records, artists => artists_records # music_artists, music_records => music_artists_records def self.derive_join_table_name(first_table, second_table) # :nodoc: [first_table.to_s, second_table.to_s].sort.join("\0").gsub(/^(.*_)(.+)\0\1(.+)/, '\1\2_\3').tr("\0", "_") end module ClassMethods # Guesses the table name (in forced lower-case) based on the name of the class in the # inheritance hierarchy descending directly from ActiveRecord::Base. So if the hierarchy # looks like: Reply < Message < ActiveRecord::Base, then Message is used # to guess the table name even when called on Reply. The rules used to do the guess # are handled by the Inflector class in Active Support, which knows almost all common # English inflections. You can add new inflections in config/initializers/inflections.rb. # # Nested classes are given table names prefixed by the singular form of # the parent's table name. Enclosing modules are not considered. # # ==== Examples # # class Invoice < ActiveRecord::Base # end # # file class table_name # invoice.rb Invoice invoices # # class Invoice < ActiveRecord::Base # class Lineitem < ActiveRecord::Base # end # end # # file class table_name # invoice.rb Invoice::Lineitem invoice_lineitems # # module Invoice # class Lineitem < ActiveRecord::Base # end # end # # file class table_name # invoice/lineitem.rb Invoice::Lineitem lineitems # # Additionally, the class-level +table_name_prefix+ is prepended and the # +table_name_suffix+ is appended. So if you have "myapp_" as a prefix, # the table name guess for an Invoice class becomes "myapp_invoices". # Invoice::Lineitem becomes "myapp_invoice_lineitems". # # You can also set your own table name explicitly: # # class Mouse < ActiveRecord::Base # self.table_name = "mice" # end def table_name reset_table_name unless defined?(@table_name) @table_name end # Sets the table name explicitly. Example: # # class Project < ActiveRecord::Base # self.table_name = "project" # end def table_name=(value) value = value && value.to_s if defined?(@table_name) return if value == @table_name reset_column_information if connected? end @table_name = value @quoted_table_name = nil @arel_table = nil @sequence_name = nil unless defined?(@explicit_sequence_name) && @explicit_sequence_name @predicate_builder = nil end # Returns a quoted version of the table name, used to construct SQL statements. def quoted_table_name @quoted_table_name ||= connection.quote_table_name(table_name) end # Computes the table name, (re)sets it internally, and returns it. def reset_table_name #:nodoc: self.table_name = if abstract_class? superclass == Base ? nil : superclass.table_name elsif superclass.abstract_class? superclass.table_name || compute_table_name else compute_table_name end end def full_table_name_prefix #:nodoc: (parents.detect { |p| p.respond_to?(:table_name_prefix) } || self).table_name_prefix end def full_table_name_suffix #:nodoc: (parents.detect { |p| p.respond_to?(:table_name_suffix) } || self).table_name_suffix end # Defines the name of the table column which will store the class name on single-table # inheritance situations. # # The default inheritance column name is +type+, which means it's a # reserved word inside Active Record. To be able to use single-table # inheritance with another column name, or to use the column +type+ in # your own model for something else, you can set +inheritance_column+: # # self.inheritance_column = 'zoink' def inheritance_column (@inheritance_column ||= nil) || superclass.inheritance_column end # Sets the value of inheritance_column def inheritance_column=(value) @inheritance_column = value.to_s @explicit_inheritance_column = true end def sequence_name if base_class == self @sequence_name ||= reset_sequence_name else (@sequence_name ||= nil) || base_class.sequence_name end end def reset_sequence_name #:nodoc: @explicit_sequence_name = false @sequence_name = connection.default_sequence_name(table_name, primary_key) end # Sets the name of the sequence to use when generating ids to the given # value, or (if the value is +nil+ or +false+) to the value returned by the # given block. This is required for Oracle and is useful for any # database which relies on sequences for primary key generation. # # If a sequence name is not explicitly set when using Oracle, # it will default to the commonly used pattern of: #{table_name}_seq # # If a sequence name is not explicitly set when using PostgreSQL, it # will discover the sequence corresponding to your primary key for you. # # class Project < ActiveRecord::Base # self.sequence_name = "projectseq" # default would have been "project_seq" # end def sequence_name=(value) @sequence_name = value.to_s @explicit_sequence_name = true end # Determines if the primary key values should be selected from their # corresponding sequence before the insert statement. def prefetch_primary_key? connection.prefetch_primary_key?(table_name) end # Returns the next value that will be used as the primary key on # an insert statement. def next_sequence_value connection.next_sequence_value(sequence_name) end # Indicates whether the table associated with this class exists def table_exists? connection.schema_cache.data_source_exists?(table_name) end def attributes_builder # :nodoc: @attributes_builder ||= AttributeSet::Builder.new(attribute_types, primary_key) do |name| unless columns_hash.key?(name) _default_attributes[name].dup end end end def columns_hash # :nodoc: load_schema @columns_hash end def columns load_schema @columns ||= columns_hash.values end def attribute_types # :nodoc: load_schema @attribute_types ||= Hash.new(Type.default_value) end def yaml_encoder # :nodoc: @yaml_encoder ||= AttributeSet::YAMLEncoder.new(attribute_types) end # Returns the type of the attribute with the given name, after applying # all modifiers. This method is the only valid source of information for # anything related to the types of a model's attributes. This method will # access the database and load the model's schema if it is required. # # The return value of this method will implement the interface described # by ActiveModel::Type::Value (though the object itself may not subclass # it). # # +attr_name+ The name of the attribute to retrieve the type for. Must be # a string def type_for_attribute(attr_name, &block) if block attribute_types.fetch(attr_name, &block) else attribute_types[attr_name] end end # Returns a hash where the keys are column names and the values are # default values when instantiating the Active Record object for this table. def column_defaults load_schema @column_defaults ||= _default_attributes.to_hash end def _default_attributes # :nodoc: @default_attributes ||= AttributeSet.new({}) end # Returns an array of column names as strings. def column_names @column_names ||= columns.map(&:name) end # Returns an array of column objects where the primary id, all columns ending in "_id" or "_count", # and columns used for single table inheritance have been removed. def content_columns @content_columns ||= columns.reject do |c| c.name == primary_key || c.name == inheritance_column || c.name.end_with?("_id") || c.name.end_with?("_count") end end # Resets all the cached information about columns, which will cause them # to be reloaded on the next request. # # The most common usage pattern for this method is probably in a migration, # when just after creating a table you want to populate it with some default # values, eg: # # class CreateJobLevels < ActiveRecord::Migration[5.0] # def up # create_table :job_levels do |t| # t.integer :id # t.string :name # # t.timestamps # end # # JobLevel.reset_column_information # %w{assistant executive manager director}.each do |type| # JobLevel.create(name: type) # end # end # # def down # drop_table :job_levels # end # end def reset_column_information connection.clear_cache! undefine_attribute_methods connection.schema_cache.clear_data_source_cache!(table_name) reload_schema_from_cache initialize_find_by_cache end protected def initialize_load_schema_monitor @load_schema_monitor = Monitor.new end private def inherited(child_class) super child_class.initialize_load_schema_monitor end def schema_loaded? defined?(@schema_loaded) && @schema_loaded end def load_schema return if schema_loaded? @load_schema_monitor.synchronize do return if defined?(@columns_hash) && @columns_hash load_schema! @schema_loaded = true end end def load_schema! @columns_hash = connection.schema_cache.columns_hash(table_name).except(*ignored_columns) @columns_hash.each do |name, column| define_attribute( name, connection.lookup_cast_type_from_column(column), default: column.default, user_provided_default: false ) end end def reload_schema_from_cache @arel_engine = nil @arel_table = nil @column_names = nil @attribute_types = nil @content_columns = nil @default_attributes = nil @column_defaults = nil @inheritance_column = nil unless defined?(@explicit_inheritance_column) && @explicit_inheritance_column @attributes_builder = nil @columns = nil @columns_hash = nil @schema_loaded = false @attribute_names = nil @yaml_encoder = nil direct_descendants.each do |descendant| descendant.send(:reload_schema_from_cache) end end # Guesses the table name, but does not decorate it with prefix and suffix information. def undecorated_table_name(class_name = base_class.name) table_name = class_name.to_s.demodulize.underscore pluralize_table_names ? table_name.pluralize : table_name end # Computes and returns a table name according to default conventions. def compute_table_name base = base_class if self == base # Nested classes are prefixed with singular parent table name. if parent < Base && !parent.abstract_class? contained = parent.table_name contained = contained.singularize if parent.pluralize_table_names contained += "_" end "#{full_table_name_prefix}#{contained}#{undecorated_table_name(name)}#{full_table_name_suffix}" else # STI subclasses always use their superclass' table. base.table_name end end end end end