require 'active_support/concern' require 'active_support/core_ext/class/attribute_accessors' module ActiveRecord module ModelSchema extend ActiveSupport::Concern ## # :singleton-method: # Accessor for 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. Configuration.define :primary_key_prefix_type included do ## # :singleton-method: # Accessor for the name of 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. class_attribute :table_name_prefix, :instance_writer => false self.table_name_prefix = "" ## # :singleton-method: # 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. class_attribute :table_name_suffix, :instance_writer => false self.table_name_suffix = "" ## # :singleton-method: # 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. class_attribute :pluralize_table_names, :instance_writer => false self.pluralize_table_names = true 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 # # Alternatively, you can override the table_name method to define your # own computation. (Possibly using super to manipulate the default # table name.) Example: # # class Post < ActiveRecord::Base # def self.table_name # "special_" + super # end # end # Post.table_name # => "special_posts" 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 # # You can also just define your own self.table_name method; see # the documentation for ActiveRecord::Base#table_name. def table_name=(value) @original_table_name = @table_name if defined?(@table_name) @table_name = value @quoted_table_name = nil @arel_table = nil @relation = Relation.new(self, arel_table) 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: if active_record_super.abstract_class? self.table_name = active_record_super.table_name || compute_table_name elsif abstract_class? self.table_name = active_record_super == Base ? nil : active_record_super.table_name else self.table_name = 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 # The name of the column containing the object's class when Single Table Inheritance is used def inheritance_column if self == Base 'type' else (@inheritance_column ||= nil) || active_record_super.inheritance_column end end # Sets the value of inheritance_column def inheritance_column=(value) @original_inheritance_column = inheritance_column @inheritance_column = value.to_s 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: self.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 or Firebird, # 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) @original_sequence_name = @sequence_name if defined?(@sequence_name) @sequence_name = value.to_s end # Indicates whether the table associated with this class exists def table_exists? connection.schema_cache.table_exists?(table_name) end # Returns an array of column objects for the table associated with this class. def columns @columns ||= connection.schema_cache.columns[table_name].map do |col| col = col.dup col.primary = (col.name == primary_key) col end end # Returns a hash of column objects for the table associated with this class. def columns_hash @columns_hash ||= Hash[columns.map { |c| [c.name, c] }] end # Returns a hash where the keys are column names and the values are # default values when instantiating the AR object for this table. def column_defaults @column_defaults ||= Hash[columns.map { |c| [c.name, c.default] }] end # Returns an array of column names as strings. def column_names @column_names ||= columns.map { |column| column.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 { |c| c.primary || c.name =~ /(_id|_count)$/ || c.name == inheritance_column } end # Returns a hash of all the methods added to query each of the columns in the table with the name of the method as the key # and true as the value. This makes it possible to do O(1) lookups in respond_to? to check if a given method for attribute # is available. def column_methods_hash #:nodoc: @dynamic_methods_hash ||= column_names.inject(Hash.new(false)) do |methods, attr| attr_name = attr.to_s methods[attr.to_sym] = attr_name methods["#{attr}=".to_sym] = attr_name methods["#{attr}?".to_sym] = attr_name methods["#{attr}_before_type_cast".to_sym] = attr_name methods 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 # 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_table_cache!(table_name) if table_exists? @column_names = @content_columns = @column_defaults = @columns = @columns_hash = nil @dynamic_methods_hash = @inheritance_column = nil @arel_engine = @relation = nil end def clear_cache! # :nodoc: connection.schema_cache.clear! end private # 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 table_name = table_name.pluralize if pluralize_table_names 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 < ActiveRecord::Model && !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)}#{table_name_suffix}" else # STI subclasses always use their superclass' table. base.table_name end end end end end