Class: Sequel::MigrationDSL

Inherits:
BasicObject
Defined in:
lib/sequel/extensions/migration.rb

Overview

Internal class used by the Sequel.migration DSL, part of the migration extension.

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from BasicObject

const_missing

Constructor Details

#initialize(&block) ⇒ MigrationDSL

Create a new migration class, and instance_exec the block.



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# File 'lib/sequel/extensions/migration.rb', line 125

def initialize(&block)
  @migration = SimpleMigration.new
  Migration.descendants << migration
  instance_exec(&block)
end

Instance Attribute Details

#migration ⇒ Object (readonly)

The underlying SimpleMigration instance



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# File 'lib/sequel/extensions/migration.rb', line 118

def migration
  @migration
end

Class Method Details

.create(&block) ⇒ Object 



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# File 'lib/sequel/extensions/migration.rb', line 120

def self.create(&block)
  new(&block).migration
end

Instance Method Details

#change(&block) ⇒ Object

Creates a reversible migration. This is the same as creating the same block with up, but it also calls the block and attempts to create a down block that will reverse the changes made by the block.

There are no guarantees that this will work perfectly in all cases, but it works for some simple cases.



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# File 'lib/sequel/extensions/migration.rb', line 158

def change(&block)
  migration.up = block
  migration.down = MigrationReverser.new.reverse(&block)
end

#down(&block) ⇒ Object

Defines the migration’s down action.



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# File 'lib/sequel/extensions/migration.rb', line 132

def down(&block)
  migration.down = block
end

#no_transaction ⇒ Object

Disable the use of transactions for the related migration



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# File 'lib/sequel/extensions/migration.rb', line 137

def no_transaction
  migration.use_transactions = false
end

#revert(&block) ⇒ Object

Creates a revert migration. This is the same as creating the same block with down, but it also calls the block and attempts to create a up block that will reverse the changes made by the block. This is designed to revert the changes in the provided block.

There are no guarantees that this will work perfectly in all cases, but it works for some simple cases.



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# File 'lib/sequel/extensions/migration.rb', line 171

def revert(&block)
  migration.down = block
  migration.up = MigrationReverser.new.reverse(&block)
end

#transaction ⇒ Object

Enable the use of transactions for the related migration



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# File 'lib/sequel/extensions/migration.rb', line 142

def transaction
  migration.use_transactions = true
end

#up(&block) ⇒ Object

Defines the migration’s up action.



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# File 'lib/sequel/extensions/migration.rb', line 147

def up(&block)
  migration.up = block
end