Table of Contents
In Berkeley DB, a database is a collection of records. Records, in turn, consist of key/data pairings.
	Conceptually, you can think of a 
		
		database 
	as containing a two-column table where column 1 contains a key and column 2
	contains data.  Both the key and the data are managed using 
		 
		
		Dbt
		class instances
		
	(see Database Records for details on this 
	    class
	    ).
	So, fundamentally, using a DB 
		 
		database 
	involves putting, getting, and deleting database records, which in turns involves efficiently 
	managing information 
		encapsulated by 
		
		
		 
		
		Dbt
		
		objects.
		
	The next several chapters of this book are dedicated to those activities.
  
        You open a database by instantiating a Db object
        and then calling its open() method.
    
		Note that by default, DB does not create databases if they do not already exist. 
		To override this behavior, specify the 
		DB_CREATE flag on the
		open() method.
	
The following code fragment illustrates a database open:
#include <db_cxx.h>
...
Db db(NULL, 0);               // Instantiate the Db object
u_int32_t oFlags = DB_CREATE; // Open flags;
try {
    // Open the database
    db.open(NULL,                // Transaction pointer 
            "my_db.db",          // Database file name 
            NULL,                // Optional logical database name
            DB_BTREE,            // Database access method
            oFlags,              // Open flags
            0);                  // File mode (using defaults)
// DbException is not subclassed from std::exception, so
// need to catch both of these.
} catch(DbException &e) {
    // Error handling code goes here    
} catch(std::exception &e) {
    // Error handling code goes here
}