DB means Data Byte(s). Well, this keyword enables you to enumerate bytes or strings.
As you can see the picture above, you can give bytes by numbers (binary, decimal, hexadecimal) and strings (chars). These values are stored as bytes, this means if you give 256 then DB stores 0, because of 256 is 1|0000|0000 in binary and only the lower 8-bits count.
If you give an "empty"-value or values such as TIMES",,, at the end of the 25th line, it will be TIMES",0,0,0 ...BUT... the TIMES",256,256,256 is the same, too.