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mod_db implements an API and dialplan interface to a database backend. The database can either be in sqlite or ODBC. It also provides support for group dialing and provides database backed limit interface.

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ODBC must be configured to use ODBC resources (configure with --enable-core-odbc-support).


mod_db is compiled and loaded by default. Modify db.conf to enable ODBC.


Realm and key are arbitrary strings. Consider realm as a container for keys.

Dialplan Application


Insert a value into the database:

<action application="db" data="insert/realm/key/value"/>

mod_db manages 'realm/key' as a UNIQUE tuple (2-tuple). So if you 'insert' two, or more, times the same 'realm/key' tuple, then only one row, of 'realm/key/value', will be in the persistent database. The one-only stored row is the row resulting from the last successful 'insert/realm/key/value' method (last-in). Method 'select/realm/key' returns this last-in, one-only resulting row.

As of 2013-05-08, newly created schemas enforce this uniqueness with an index. Previous versions only maintain it internally with a SQL delete + insert.

Delete an entry from the database:

<action application="db" data="delete/realm/key"/>

Retrieve a value from the database:

<action application="set" data="var=${db(select/realm/key)}"/>

Use as a condition:

<condition field="${db(select/realm/key)}" expression="^value$"/>

Use as a condition checking if item exists:

<condition field="${db(exists/realm/key)}" expression="^true$"/>


Group allows one to define multiple endpoints for a given destination (group).

Insert a group entry:

<action application="group" data="insert:groupname:sipurl"/> 

Delete a group entry:

 <action application="group" data="delete:groupname:sipurl"/>

Select a group entry:

 <action application="set" data="api_result=${group(call:groupname)}"/>



db insert/realm/key/value
db delete/realm/key
db select/realm/key
db exists/realm/key


group insert:groupname:sipurl
group delete:groupname:sipurl
group call:groupname[:order]


The db backend for limit provides a persistent datastore for limit data. If using ODBC, this backend can also be shared across a cluster of FreeSWITCH™ instances.

This backend does NOT support rate based limits.