Dynamic extensions

I have created a dynamic realtime system used to register extensions on database instead of writing configuration of extensions in sip.conf.

if we have a configuration for extensions in file sip.conf, the system skip database configuration and use one in sip.conf,

i added the following to extconfig.conf

sippeers => odbc,MySQL-asterisk,sip_conf sipusers => odbc,MySQL-asterisk,sip_conf
with database table “sip_conf”

how can i force first priority of registration for database?