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()
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# File lib/sequel/extensions/migration.rb 168 def initialize 169 @actions = [] 170 end
Public Instance Methods
reverse(&block)
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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 175 def reverse(&block) 176 begin 177 instance_exec(&block) 178 rescue 179 just_raise = true 180 end 181 if just_raise 182 Proc.new{raise Sequel::Error, "irreversible migration method used in #{block.source_location.first}, you may need to write your own down method"} 183 else 184 actions = @actions.reverse 185 Proc.new do 186 actions.each do |a| 187 pr = a.last.is_a?(Proc) ? a.pop : nil 188 # Allow calling private methods as the reversing methods are private 189 send(*a, &pr) 190 end 191 end 192 end 193 end
Private Instance Methods
add_column(*args)
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# File lib/sequel/extensions/migration.rb 197 def add_column(*args) 198 @actions << [:drop_column, args[0], args[1]] 199 end
add_index(*args)
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# File lib/sequel/extensions/migration.rb 201 def add_index(*args) 202 @actions << [:drop_index, *args] 203 end
alter_table(table, &block)
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# File lib/sequel/extensions/migration.rb 205 def alter_table(table, &block) 206 @actions << [:alter_table, table, MigrationAlterTableReverser.new.reverse(&block)] 207 end
create_enum(name, _)
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# File lib/sequel/extensions/pg_enum.rb 188 def create_enum(name, _) 189 @actions << [:drop_enum, name] 190 end
create_join_table(*args)
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# File lib/sequel/extensions/migration.rb 209 def create_join_table(*args) 210 @actions << [:drop_join_table, *args] 211 end
create_table(name, opts=OPTS)
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# File lib/sequel/extensions/migration.rb 213 def create_table(name, opts=OPTS) 214 @actions << [:drop_table, name, opts] 215 end
create_view(name, _, opts=OPTS)
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# File lib/sequel/extensions/migration.rb 217 def create_view(name, _, opts=OPTS) 218 @actions << [:drop_view, name, opts] 219 end
rename_column(table, name, new_name)
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# File lib/sequel/extensions/migration.rb 221 def rename_column(table, name, new_name) 222 @actions << [:rename_column, table, new_name, name] 223 end
rename_enum(old_name, new_name)
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# 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)
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# File lib/sequel/extensions/migration.rb 225 def rename_table(table, new_name) 226 @actions << [:rename_table, new_name, table] 227 end