问用外键从CSV提取和导入数据. Postgresql

EN

    create or replace procedure generate_user_idents() 
      language sql $
        insert into identities(name, email)
             select name, email
               from stage
              on conflict (low_email) 
                  do nothing ; 
                 
    as $$
        insert into users(ident_id) 
             select ident.ident_id 
               from identities ident 
              where ident.low_email in 
                    ( select lower(email) 
                        from stage
                    ) ;
                   
    $$;  

    do $$
    begin
        execute 'truncate table stage'; 
    
       -- replace the following with your \copy to load stage 
        insert into stage(name, email)
             values ( 'Alon muscle', 'muscle@test.com' )
                  , ( 'watson',      'watson@watson.com')         
                  , ( 'james',       'james@james.com' ); 
            
        call generate_user_idents(); 
    end ; 
    $$;