class ActiveRecord::Schema - activerecord-4.2.4 Documentation

# class ActiveRecord::Schema

# 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.

### Public Class Methods

define(info={}, &block) click to toggle source

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`, `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

    # File lib/active_record/schema.rb, line 60
    def self.define(info={}, &block)
      new.define(info, &block)
    end

### Public Instance Methods

migrations_paths() click to toggle source

Returns the migrations paths.

    ActiveRecord::Schema.new.migrations_paths
    # => ["db/migrate"] # Rails migration path by default.

    # File lib/active_record/schema.rb, line 36
    def migrations_paths
      ActiveRecord::Migrator.migrations_paths
    end