[Serusers] Questions about avp_db_load() at avpops module

[Charles Wang]

Dear ALL:

I have defined these lines at my ser.cfg.

modparam("avpops", "avp_url", "mysql://ser:heslo@localhost/ser")
modparam("avpops", "avp_table", "usr_preferences")
modparam("avpops", "uuid_column", "uuid")
modparam("avpops", "username_column", "username")
modparam("avpops", "domain_column", "domain")
modparam("avpops", "attribute_column", "attribute")
modparam("avpops", "value_column", "value")
modparam("avpops", "type_column", "type")
modparam("avpops", "avp_aliases",
"voicemail=i:500;calltype=i:700;fwd_no_answer_type=i:701;fwd_busy_type=i:702")

Q1: But I don't know what it mean about 700 or 701. Is it a numeric ID
of one UA?

And I have refered to http://www.voice-system.ro/docs/avpops

And find many examples in it.

But I still can't understand what it mean about avp_db_load().

my avp table is named as "usr_preferences" and it is empty before I
use avpops modules.

Q2: Is it should have some initilized records in it?
     Otherwise, what will be loaded with avp_db_load()?

For this web page said:
    avp_db_load("$ruri/domain","i:/domain_preferences");
               - loads all AVPs with ID from 'domain_preferences'
                 table for domain from RURI
Q3: Is "$ruri" the caller user's URI? and the "domain" is the same?
     Is "domain_preferences"  table name? Is it equal to my "usr_preferences"?
     Or it is just a virtual table in memory?

Thank you for your answer my stupid questions.

Charles