MySQL 8.0

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create table persons( 
  uuid varchar( 100 ) 
, persons_cover varchar( 100 ) 
, constraint persons_pkey primary key ( uuid, persons_cover )
) ;
create table files (
  uuid varchar( 100 )
, model varchar( 100 )
) ;
alter table files
add constraint fk_persons_cover
foreign key( uuid, model ) references persons( uuid, persons_cover ) ;

Records: 0  Duplicates: 0  Warnings: 0


create table persons2( 
  uuid varchar( 100 ) 
, persons_cover varchar( 100 ) 
, constraint persons_pkey primary key ( uuid )
) ;
alter table files
add constraint fk_persons_cover2
foreign key( uuid, model ) references persons2( uuid, persons_cover ) ;

Failed to add the foreign key constraint. Missing index for constraint 'fk_persons_cover2' in the referenced table 'persons2'


alter table persons2 
add constraint upc_unique unique( uuid, persons_cover ) ;

Records: 0  Duplicates: 0  Warnings: 0


alter table files
add constraint fk_persons_cover2
foreign key( uuid, model ) references persons2( uuid, persons_cover ) 
on delete no action
on update no action 
;

Records: 0  Duplicates: 0  Warnings: 0