CommDb

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Created: ivey (21 Mar 2007)

Last edited: hamishwillee (20 Jul 2012)

Introduction

The communications database known as CommDb is a Symbian OS database which is managed by the Symbian OS DBMS system. Basically, this provides a system-wide storage for communications related settings.

This is mostly used by applications and other communications sub-systems, such as, Telephony and WAP to store component configuration information. This kind stored content in the database can be accessed and updated by using CommDb APIs provided by Symbian OS.These APIs allow multiple clients/connections to access the database concurrently.

Architecture

CommDb stores the settings in a series of tables in a relational database, using the DBMS architecture. DBMS is a client/server architecture and provides for safe access by multiple clients. It holds information about:

• Internet Access Providers (IAPs)
• Internet Service Providers (ISPs)
• GPRS
• modems
• locations
• charge-cards
• proxies and WAP settings.

CommDB Interface

The CommDb interface allows clients to access the database, open its tables and perform different transactions. It is provided by CCommsDatabase and its base class CCommsDatabaseBase. In CommDb interface, access to a Table in a database is provided by CCommsDbTableView.

class CCommsDbTableView : public CBase;

We need the type of table we want to access while making use of the CommDb APIs, so some specific types of tables are as follows:

• Chargecard table
• Connection preferences table
• Dial-out ISP table
• Global table
• IAP table: an Internet Access Point (IAP) defines sets of ISP and chargecard that can be used together
• Incoming GPRS table
• Location table: affects how telephone numbers are dialled
• Modems table
• Outgoing GPRS table
• Proxies table
• WAP access point table
• WAP IP bearer table
• WAP SMS bearer table

CommDB Editor

The CommDB Editor is a PC tool that allows us to view and edit CommDB in the emulator. It is a useful tool, especially for developers who are still new to CommDB. It shows the table structure of CommDB and the value of its fields (see picture below).

For more information, how to import and export CommDB to this editor, please read Configuring Comms Database using CEDDUMP and CED.

Related

• http://symbian.newlc.com/A-few-notes-about-the-CommDb.html
• Symbian FAQ-1071
• DBMS - Symbian databases
• Reading internet access points from the device (code example)
• Creating the GPRS Internet Access Point (IAP) (code example)