Are there reasons why the function 'hash' (non-persistent storage) and function 'db' (persistent storage) share a look-a-like user interface (e.g. select/insert/delete) but do not work-a-like. In particular, in 'hash', insert overwrites an identical realm/data_key pair whereas 'db' , in so far as I can tell, just blindly adds, and adds, adds, the insert(s). However, the 'db' select method returns one record only even if the db has accumulated many realm/data_key records, including data_value duplicates. NOTWITHSTANDING reasons-unknow-to-me, a remedy to harmonize the non-persistent 'hash' with the persistent 'db' I *think* is straight forward ... (1) At the call_limit.db schema-level, a one-time create UNIQUE COMPOUND index, as follows, CREATE UNIQUE INDEX IF NOT EXISTS 'idx_db_data_HostRealmDK' ON 'db_data' ('hostname','realm','data_key'); (1) At the c-language embedded SQL string-level, change the existing INSERT to be the following, INSERT OR REPLACE INTO db_data (hostname,realm,data_key,data) VALUES (%s,%s,%s,%s); The index will help speed UP the reads. Neither change is "exotic" and should be portable across standard sql implementations. ;-) ... thoughts ? Thanks,