DB : module{	PATH : con "/dis/lib/db.dis"; 	# Open the connection to the DB server    	# returns (New handle, "") or (nil, "Error Message")	#	open:	fn(addr, username, password, dbname: string) :					(ref DB_Handle, list of string);	#	# Opens a connection to an Inferno on the database machine, with the	# specified level of security.	# 	connect : fn(addr, alg : string) : (ref Sys->FD, string);	#	# Mounts the file descriptor on dir, then opens the database.	#	dbopen: fn(fd : ref Sys->FD, username, password, dbname : string) :						(ref DB_Handle, list of string); 	DB_Handle : adt	{		#		# Open another SQL stream for the same connection.		#		SQLOpen :	fn(oldh : self ref DB_Handle) : (int, ref DB_Handle);		SQLClose : fn(dbh : self ref DB_Handle) : int; 	                   # Execute the SQL command		# returns (0, "") or (error code, "Message")		#	    	SQL:	fn(handle: self ref DB_Handle, command: string)							: (int, list of string); 		# Check the number of columns of last select command		#		columns:	fn(handle: self ref DB_Handle): int; 		# Fetch the next row of the selection results.		# returns current row number, or 0		#	  	nextRow:	fn(handle: self ref DB_Handle): int;	 		# Read the data of column[i] of current row		#	  	read:	fn(handle: self ref DB_Handle, column: int)							: (int, array of byte); 		# Write data to be used for parameter[i]		#		write:	fn(handle: self ref DB_Handle, column: int,						fieldval: array of byte) : int; 		# Title of the column[i]		#	  	columnTitle: 	fn(handle: self ref DB_Handle, column: int)							: string; 		#error message associated with last command		#		errmsg:		fn(handle: self ref DB_Handle): string; 		datafd : ref Sys->FD;		sqlconn:int;		sqlstream : int;		lock : chan of int; 	};};