#7 obo2chado update notes

[Anonymous]

obo2chado works for updating ontologies such as SO with a few caveats

(1) We need to review handling of renamed terms. Currently in obo2chado, if a term name is updated with no change to the ID, a new cvterm term is added. The result is multiple cvterms with the same dbxref accession. This is not a problem for Chado and may be the desired behavior but need to ask around.

(2)Append mode will duplicate data in cvtermprop,cvterm_dbxref,cvtermsynonym if this data already exists in the database. At least for cvtermprop, the problem appears to be from comments in the SO file that are not handled if they are already loaded.