anchor.diff:  %%   * some options can't be changed
   %% - perform change options in appropriate order
   %%
  +%% Note:
  +%% - if table size = 0, we can skip some actions
  +%%   * e.g., copying not needed
  +%% - if table size is small, we can do different
  +%%   strategy than if table is large
  +%%   * small table can migrate via ram_copies
  +%%
   %% UNFINISHED
   %% - what is the correct order of actions?
   %%   e.g., change table opts before or after layout, etc
  
positive.code: %% - derive a schema from current db
  %% - verify that current db complies with schema 
  %%
  %% NOTE: looks like fragmented tables are explicitly
  %%  updated to frag status, rather than declaring them.
  %%  Thus, schematool should provide a declarative approach.
  %%
  %% UNFINISHED
  %% 1/ collect ALL of the changes in one call
  
negative.code: 	      %% Handled by alter_storage_type
  	      Actions;
  	 ({ram_copies, Ns}, Actions) ->
  	      %% Handled by alter_storage_type
  	      Actions;
  	 ({disc_only_copies, Ns}, Actions) ->
  	      %% Handled by alter_storage_type
  