Create a shortcut in Desktop or where you want and on the shortcut properties tab you can set the start directory. That way you can init DB with all the commands you want and be able to use the plugins since the start directory is the same as where DB is.
Thanks for the tips.
But I am using a customized relogger written by JAVA, it might be hard to specify the start directory, and I noticed other plugin using some more stable function to do path job. Like Giles:
string sDemonBuddyPath = Assembly.GetEntryAssembly().Location;
sTrinityPluginPath = Path.GetDirectoryName(sDemonBuddyPath) + @"\Plugins\GilesTrinity\";
sTrinityConfigFile = Path.GetDirectoryName(sDemonBuddyPath) + @"\Settings\GilesTrinity.cfg";
That would be more reliable in most of situations.