    blastp -query homo.faa -db cow.faa -out homo_blast.csv -outfmt 6 -evalue 0.00001 -max_target_seqs 1 -num_threads 32

  
I got the below error while performing protein blast with the code mentioned above

> BLAST Database error: No alias or index file found for protein
> database [cow.faa] in search path

When I revised the code by specifying the path, the problem was not resolved. When I typed subject instead of db, the problem was solved, but I'm not sure if it's correct.
When you use a `-db` switch, it is expected that your database will be indexed. This is done using a `makeblastdb` command, and will create several files that will end in `.p??` where ?? stands for two other letters. When searching against a large database, to gain speed you would want to index it and use a `-db` switch. You most likely have not done this step.

When using a `-subject` switch, the database need not be indexed. The result will be the same as when using the `-db` switch, but the search will be slower and this is not recommended for larger databases. It is typically used for comparing two sequences, or when the target database is relatively small.