text: -- New field in archive table to preserve text source IDs across undeletion.
  --
  -- Older entries containing NULL in this field will contain text in the
  -- ar_text and ar_flags fields, and will cause the (re)creation of a new
  -- text record upon undeletion.
  --
  -- Newer ones will reference a text.old_id with this field, and the existing
  -- entries will be used as-is; only a revision record need be created.
  --
  -- Added 2005-05-01
  
  ALTER TABLE /*$wgDBprefix*/archive
    ADD
      ar_text_id int unsigned;
  