schemas/vegbien.sql: aggregateoccurrence: Made taxonoccurrence_id optional when sourceaccessioncode is specified, so that aggregateoccurrence doesn't get pruned away in datasource tables that link just a stemobservation to a plantobservation (and therefore don't provide a taxonoccurrence to satisfy the previous taxonoccurrence_id NOT NULL constraint)

schemas/vegbien.sql: aggregateoccurrence: Made taxonoccurrence_id optional when sourceaccessioncode is specified, so that aggregateoccurrence doesn't get pruned away in datasource tables that link just a stemobservation to a plantobservation (and therefore don't provide a taxonoccurrence to satisfy the previous taxonoccurrence_id NOT NULL constraint)

schemas/vegbien.sql: taxonoccurrence: Added taxonoccurrence_required_key check constraint to ensure that all taxonoccurrences are properly identified, and empty taxonoccurrences are properly pruned. This fixes a bug where taxon-only and stem-only data did not properly prune the taxonoccurrence that would otherwise get created because it's included in the mappings.

sql_io.py: put_table(): insert_into_pkeys(): Use new sql.add_pkey_or_index() instead of sql.add_pkey() in order to just print a warning if for some reason there were duplicate entries for an input row in the iteration's pkeys table. This should provide a workaround for bugs (often in the schema itself, related to its unique indexes) that cause an input row to match multiple output rows when joining on the output table using the unique constraint's columns.

sql.py: Added add_pkey_or_index()

sql.py: parse_exception(): Parse "could not create unique index ... Key is duplicated" errors as DuplicateKeyException

sql.py: parse_exception(): DuplicateKeyException: Factored out creation of DuplicateKeyException into helper function

inputs/import.stats.xls: Updated import times

tnrs_db: Removed tnrs.InvalidResponse exception handler that retries the query because the current query does not track which names have been submitted to but not processed by TNRS, so the error would continue to happen repeatedly

schemas/vegbien.sql: location: Added index on parent_id to speed up plot change over time joins