module ActiveRecord # = Active Record \Schema # # Allows programmers to programmatically define a schema in a portable # DSL. This means you can define tables, indexes, etc. without using SQL # directly, so your applications can more easily support multiple # databases. # # Usage: # # ActiveRecord::Schema.define do # create_table :authors do |t| # t.string :name, null: false # end # # add_index :authors, :name, :unique # # create_table :posts do |t| # t.integer :author_id, null: false # t.string :subject # t.text :body # t.boolean :private, default: false # end # # add_index :posts, :author_id # end # # ActiveRecord::Schema is only supported by database adapters that also # support migrations, the two features being very similar. class Schema < Migration::Current # Eval the given block. All methods available to the current connection # adapter are available within the block, so you can easily use the # database definition DSL to build up your schema ( # {create_table}[rdoc-ref:ConnectionAdapters::SchemaStatements#create_table], # {add_index}[rdoc-ref:ConnectionAdapters::SchemaStatements#add_index], etc.). # # The +info+ hash is optional, and if given is used to define metadata # about the current schema (currently, only the schema's version): # # ActiveRecord::Schema.define(version: 20380119000001) do # ... # end def self.define(info = {}, &block) new.define(info, &block) end def define(info, &block) # :nodoc: instance_eval(&block) if info[:version].present? initialize_schema_migrations_table connection.assume_migrated_upto_version(info[:version], migrations_paths) end ActiveRecord::InternalMetadata.create_table ActiveRecord::InternalMetadata[:environment] = ActiveRecord::Migrator.current_environment end private # Returns the migrations paths. # # ActiveRecord::Schema.new.migrations_paths # # => ["db/migrate"] # Rails migration path by default. def migrations_paths ActiveRecord::Migrator.migrations_paths end end end