asterisk/doc/extconfig.txt

Asterisk external configuration
===============================

The Asterisk external configuration engine is the result of work by
Anthony Minessale II, Mark Spencer and Constantine Filin.

It is designed to provide a flexible, seamless integration between
Asterisk's internal configuration structure and external SQL other other
databases (maybe even LDAP one day).

The external configuration engine is the basis for the ARA, the
Asterisk Realtime Architecture (see doc/realtime.txt for more 
information).

* Configuration

External configuration is configured in /etc/asterisk/extconfig.conf
allowing you to map any configuration file (static mappings) to
be pulled from the database, or to map special runtime entries which
permit the dynamic creation of objects, entities, peers, etc. without
the necessity of a reload.

Generally speaking, the columns in your tables should line up with the
fields you would specify in the given entity declaration.  If an entry
would appear more than once, in the column it should be separated by a
semicolon. For example, an entity that looks like:

[foo]
host=dynamic
secret=bar
context=default
context=local

could be stored in a table like this:

+------+--------+-------+--------------+----------+-----+-----------+
| name | host   | secret| context      | ipaddr   | port| regseconds|
+------+--------+-------+--------------+----------+-----+-----------+
| foo  | dynamic|  bar  | default;local| 127.0.0.1| 4569| 1096954152|
+------+--------+-------+--------------+----------+-----+-----------+

Note that for use with IAX or SIP, the table will also need the "name", 
"ipaddr", "port", "regseconds" columns.  If you wanted to be able to 
configure the callerid, you could just add a callerid column to the 
table, for example.

A SIP table would look more like this:

+------+--------+-------+----------+-----+------------+----------+
| name | host   | secret| ipaddr   | port| regseconds | username |
+------+--------+-------+----------+-----+------------+----------+
| foo  | dynamic|  bar  | 127.0.0.1| 4569| 1096954152 |   1234   |
+------+--------+-------+----------+-----+------------+----------+

in order to store appropriate parameters required for SIP.

In addition to this, if you add a field named "regserver" to the
SIP peers table and have the system name set in asterisk.conf, 
Asterisk will store the system name that the user registered on in 
the database. This can be used to direct calls to go through the server 
that holds the registration (for NAT traversal purposes).

A Voicemail table would look more like this:

+----------+---------+----------+----------+-----------+---------------+
| uniqueid | mailbox | context  | password |email      |   fullname    | 
+----------+---------+----------+----------+-----------+---------------+
|        1 |   1234  | default  |  4242    | a@b.com   | Joe Schmoe    | 
+----------+---------+----------+----------+-----------+---------------+

The uniqueid should be unique to each voicemail user and can be 
autoincrement.  It need not have any relation to the mailbox or context.

An extension table would look more like this:

+----------+---------+----------+-------+-----------+
| context  |  exten  | priority |  app  |  appdata  |
+----------+---------+----------+-------+-----------+
|  default |    1234 |        1 |  Dial |     Zap/1 |
+----------+---------+----------+-------+-----------+

In the dialplan you just use the Realtime switch:

[foo]
switch => Realtime

or:

[bar]
switch => Realtime/bar@extensions