class Sequel::MigrationReverser

Handles the reversing of reversible migrations. Basically records supported methods calls, translates them to reversed calls, and returns them in reverse order.

:nocov:

Public Class Methods

new() click to toggle source
    # File lib/sequel/extensions/migration.rb
181 def initialize
182   @actions = []
183 end

Public Instance Methods

reverse(&block) click to toggle source

Reverse the actions for the given block. Takes the block given and returns a new block that reverses the actions taken by the given block.

    # File lib/sequel/extensions/migration.rb
188 def reverse(&block)
189   begin
190     instance_exec(&block)
191   rescue
192     just_raise = true
193   end
194   if just_raise
195     Proc.new{raise Sequel::Error, "irreversible migration method used in #{block.source_location.first}, you may need to write your own down method"}
196   else
197     actions = @actions.reverse
198     Proc.new do
199       actions.each do |a|
200         pr = a.last.is_a?(Proc) ? a.pop : nil
201         # Allow calling private methods as the reversing methods are private
202         send(*a, &pr)
203       end
204     end
205   end
206 end

Private Instance Methods

add_column(*args) click to toggle source
    # File lib/sequel/extensions/migration.rb
210 def add_column(*args)
211   @actions << [:drop_column, args[0], args[1]]
212 end
add_index(*args) click to toggle source
    # File lib/sequel/extensions/migration.rb
214 def add_index(*args)
215   @actions << [:drop_index, *args]
216 end
alter_table(table, &block) click to toggle source
    # File lib/sequel/extensions/migration.rb
218 def alter_table(table, &block)
219   @actions << [:alter_table, table, MigrationAlterTableReverser.new.reverse(&block)]
220 end
create_enum(name, _) click to toggle source
    # File lib/sequel/extensions/pg_enum.rb
188 def create_enum(name, _)
189   @actions << [:drop_enum, name]
190 end
create_join_table(*args) click to toggle source
    # File lib/sequel/extensions/migration.rb
222 def create_join_table(*args)
223   @actions << [:drop_join_table, *args]
224 end
create_table(name, opts=OPTS) click to toggle source
    # File lib/sequel/extensions/migration.rb
226 def create_table(name, opts=OPTS)
227   @actions << [:drop_table, name, opts]
228 end
create_view(name, _, opts=OPTS) click to toggle source
    # File lib/sequel/extensions/migration.rb
230 def create_view(name, _, opts=OPTS)
231   @actions << [:drop_view, name, opts]
232 end
rename_column(table, name, new_name) click to toggle source
    # File lib/sequel/extensions/migration.rb
234 def rename_column(table, name, new_name)
235   @actions << [:rename_column, table, new_name, name]
236 end
rename_enum(old_name, new_name) click to toggle source
    # File lib/sequel/extensions/pg_enum.rb
192 def rename_enum(old_name, new_name)
193   @actions << [:rename_enum, new_name, old_name]
194 end
rename_table(table, new_name) click to toggle source
    # File lib/sequel/extensions/migration.rb
238 def rename_table(table, new_name)
239   @actions << [:rename_table, new_name, table]
240 end