no null constraints?

                 (sql/create-table invoices
                   [id int
                    consumer_id int
                    item_id int
                    details "varchar(640)"
                    snapshot_cap "decimal(12, 4)"
                    started int
                    executed int
                    expires int]
                   :primary-key id
                   :auto-inc id
                   :not-nulls [id item_id consumer_id started]))