123456789_123456789_123456789_123456789_123456789_

Class: ActiveRecord::Schema

Relationships & Source Files
Namespace Children
Modules:
Definition
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, Migration::Current, Migration
Instance Chain:
self, Definition, Migration::Current, Migration
Inherits: ActiveRecord::Migration::Current
Defined in: activerecord/lib/active_record/schema.rb

Overview

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[7.0].define do
create_table :authors do |t|
  t.string :name, null: false
end

add_index :authors, :name, unique: true

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

Schema is only supported by database adapters that also support migrations, the two features being very similar.

Class Method Summary

Instance Method Summary

Definition - Included

#define

Migration::Current - Inherited

#change_table, #compatible_table_definition, #create_join_table, #create_table, #drop_table

Class Method Details

.[](version)

[ GitHub ] 

  


# File 'activerecord/lib/active_record/schema.rb', line 70



def self.[](version)
  @class_for_version ||= {}
  @class_for_version[version] ||= Class.new(Migration::Compatibility.find(version)) do
    include Definition
  end
end


  








  

    .load_schema_migrations(file)  
  

  

    This method is for internal use only.
  



  

    
  





  
Raises:





  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/schema.rb', line 77



def self.load_schema_migrations(file) # :nodoc:
  # The marker is matched the way Ruby recognizes it, so files with CRLF
  # line endings or without a trailing newline load too.
  _schema, marker, data = File.read(file).rpartition(/^__END__\r?$/)

  raise ActiveRecordError, "No __END__ found in #{file}" if marker.empty?

  seen = Set.new
  versions = []

  data.each_line do |line|
    line.strip!
    next if line.empty?

    if !line.match?(/\A\d+\z/)
      raise ActiveRecordError, "Invalid migration version #{line.inspect} found after __END__"
    end

    if seen.include?(line)
      raise ActiveRecordError, "Duplicate migration version #{line.inspect} found after __END__"
    end

    seen << line
    versions << line
  end

  versions -= connection_pool.schema_migration.versions
  connection_pool.schema_migration.create_versions(versions)
end