The very first thing to do before we can begin working with a
	database, is actually connect to one.  We do this by creating a
	connection object that will serve as our "handle"
	on the connection:
      
	connection Conn("dbname=test");
      
	The connection constructor is passed one argument,
	the "connect string."  This string may be used to specify which host
	on the network runs the database backend we wish to connect to, which
	database we're interested in, which user name we'll be using to log
	in, etc.  Refer to the libpq connect call for a
	complete definition of what may go into the connect string.  In this
	case we're connecting to a database test residing
	on the local machine.  By default (if the connect string is null or
	empty, or left out, and no environment variables are set to override
	this) the client will try to connect to a server running on the local
	machine.
      
	If no connection could be established, the connection
	constructor may throw an exception immediately; or it may decide to
	retry the connection later in case the problem is only temporary.  In
	the latter case, an exception may occur at some later point if the
	problem turns out not to be so temporary after all.
      
	The connection can now act as a "service counter"
	for our database; your client will use it to perform one or more
	transactions related to the database.
      
Connections cannot be copied or assigned. Any attempt to do so will be met with a compiler error.
	  As a matter of design, libpqxx™ will not
	  allow you to perform queries on the connection
	  directly.  You will need to open a transaction instead.
	
See the section on transactions below.