text: alter table meta
      add category varChar(30) null;
  
  alter table meta drop primary key;
  
  alter table meta drop key meta_metaKey_uindex;
  
  alter table meta
      add constraint meta_pk
          unique (metaKey, category);
  
  create unique index meta_metaKey_category_uindex
      on meta (metaKey, category);
  