How to get the structure of a GDBM database

Modem Manager GUI creates a database named sms.gdbm to store all the SMS details. Currently Modem Manager GUI is not providing a feature to simply delete all received/sent messages. So I'm trying to create a program to remove those records from its database (sms.gdbm). But first I want to know the structure of the sms.gdbm database. What are the databases it contains, also table and their column names. So are there any CLI or GUI programs to display the structure of a *.gdbm file?