<html><head><meta http-equiv="Content-Type" content="text/html charset=iso-8859-1"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><br><div><div>On Thu, 6 Dec 2012, at 08:45 , "Cantor, Scott" <<a href="mailto:cantor.2@osu.edu">cantor.2@osu.edu</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><span style="font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; display: inline !important; float: none; ">Attribute standards are worthless if we try</span><br style="font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><span style="font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; display: inline !important; float: none; ">and impose constraints that aren't part of the attribute definitions.</span></blockquote></div><br></div><div>A good motto and foundation!</div><div><br></div><div>Lemmas for multi-valued attributes: </div><div><br></div><div>Attributes defined as multi-valued may have multiple values,</div><div>and if you rely on that attribute, you need to assume that it sometimes</div><div>have multiple values.</div><div><br></div><div>Attributes with multiple values have no order - not even an arbitrary </div><div>"order". Repeated responses to the identical query may return the values in</div><div>a different order. "First" or any other ordering designation can only refer to</div><div>the order in a specific instance of a response or assertion.</div><div><br></div><div>Attributes with multiple values do not entail "equivalence" or "indifference" </div><div>of the values. eduPersonAffiliation is multi-valued, but that does not</div><div>mean a service can take one of the asserted values and make that </div><div>"the" affiliation of the person. A service relying on that attribute must</div><div>be prepared to deal with multiple values or risk stupid inconsistent behavior.</div><div>Apply the same logic to givenName.</div><div><br></div><div>A service that makes the simplifying assumption that any value of</div><div>eduPerson or of givenName can be used as though it were the only</div><div>value is imposing a constraint that is not part of the attribute definition.</div><div><br></div><div>David Bantz</div><div><br></div></body></html>