[Serusers] AVPOPS syntax help

Hello list, I'm reading the documentation for AVPOPS, and Im a little confused in this section: ---------------------------------------------------------------------------- ----- #avp_db_load(source,name) #Loads from DB into memory the AVPs corresponding to the given source. Meaning of the parameters is as follows: source - what info is used for identifying the AVPs. Parameter syntax: source = (sip_uri)['/'('username'|'domain')]) | (avp_alias) | str_value sip_uri = '$from' | '$to' | '$ruri' name - which AVPs will be loaded from DB into memory. Parameter syntax is: name = avp_spec['/'(table_name|'$'db_scheme)] avp_spec = ''|'s:'|'i:'|avp_name|avp_alias Example 1-12. avp_db_load usage ... avp_db_load("$from","i:678"); avp_db_load("$ruri/domain","i:/domain_preferences"); avp_db_load("$uuid","s:404fwd/fwd_table"); avp_db_load("$ruri","i:123/$some_scheme"); ... ---------------------------------------------------------------------------- ----- My question are: Can someone explain the source syntax? Can someone explain the name syntax? what are i:, s:, avp_name and avp_alias? Thanks! Lenir