radio buttons, 367
random.asp script, 360–361
random functions, PHP and ASP, 58–59
reading and writing text files, 255–257
records, 6, 193–195, 197–200
recordset objects, requirements of, 163
recordsets, 7, 104, 162, 169
redirection mechanism, 279–280
referential integrity checks defined, 190
register.php, 371, 372–375
regular expressions
JavaScript, 235–236
PHP, 234–235
SQL, 230–232
zip codes, 237–238
relationship defined, 7
relationships, Access, 207, 208, 209, 210
Request.query String() object method in ASP, 71
require command, PHP, 161, 169
rolling back defined, 369
root element defined, 382
row defined, 6