Vlad,<br><br>exists Person(role == "parent") <br><br>checks if in workingMemory is at least one Person fact having attribute role == "parent", in both your examples.<br><br>Your reasoning is correct: the four facts with role =="child" will activate the rule. So, the result for your second example will be the same as the first result, for your list of facts, no matter how you switch the columns.<br><br>Regards,<br> Oana<br><br><b><i>"Olenin, Vladimir (MOH)" <Vladimir.Olenin@moh.gov.on.ca></i></b> wrote:<blockquote class="replbq" style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; padding-left: 5px;"> <meta http-equiv="Content-Type" content="text/html; charset=us-ascii"> <meta name="Generator" content="Microsoft Word 11 (filtered medium)"> <style> <!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {margin:0cm; margin-bottom:.0001pt; font-size:12.0pt;
font-family:"Times New Roman";} a:link, span.MsoHyperlink {color:blue; text-decoration:underline;} a:visited, span.MsoHyperlinkFollowed {color:purple; text-decoration:underline;} span.EmailStyle17 {mso-style-type:personal-compose; font-family:Arial; color:windowtext;} @page Section1 {size:612.0pt 792.0pt; margin:72.0pt 90.0pt 72.0pt 90.0pt;} div.Section1 {page:Section1;} --> </style> <div class="Section1"> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;">Hi,<o:p></o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;"><o:p> </o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;">I’m not sure my understanding of ‘existential quantifiers’ is correct. Hopefully, someone can clear it up a bit…<o:p></o:p></span></font></div> <div class="MsoNormal"><font
face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;"><o:p> </o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;">Providing I have the following fact class:<o:p></o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;"><o:p> </o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;">Person(role: parent/child, name)<o:p></o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;"><o:p> </o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;">And following facts:<o:p></o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family:
Arial;"><o:p> </o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;">1: parent, John<o:p></o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;">2: parent, Alice<o:p></o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;">3: parent, Steve<o:p></o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;">4: parent, Jane<o:p></o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;">5: child, Eric<o:p></o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;">6: child, Rob<o:p></o:p></span></font></div> <div class="MsoNormal"><font face="Arial"
size="2"><span style="font-size: 10pt; font-family: Arial;">7: child, May<o:p></o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;">8: child, April<o:p></o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;"><o:p> </o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;">I expect the rule<o:p></o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;"><o:p> </o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;">Rule “iterate children if at least one parent is found”<o:p></o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family:
Arial;">When<o:p></o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;"> exists Person(role == ‘parent’)<o:p></o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;"> $child: Person(role == ‘child’)<o:p></o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;">Then<o:p></o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;"> // do smth for each $child if at least one parent is found<o:p></o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size:
10pt; font-family: Arial;">End<o:p></o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;"><o:p> </o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;"><o:p> </o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;">To iterate through all ‘child’ persons (facts 5 through 8), ie the action will be called exactly 4 times. Is this correct? What would happen if I swap the order of the conditions (with ‘parent exists’ constrain going _<i><span style="font-style: italic;">after</span></i>_ ‘child’ constraint):<o:p></o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;"><o:p> </o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span
style="font-size: 10pt; font-family: Arial;">When<o:p></o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;"> $child: Person(role == ‘child’)<o:p></o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;"> exists Person(role == ‘parent’)<o:p></o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;"><o:p> </o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;">Thanks,<o:p></o:p></span></font></div> <div class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;"><o:p> </o:p></span></font></div> <div
class="MsoNormal"><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;">Vlad<o:p></o:p></span></font></div> </div> _______________________________________________<br>rules-users mailing list<br>rules-users@lists.jboss.org<br>https://lists.jboss.org/mailman/listinfo/rules-users<br></blockquote><br><p> 
<hr size=1>Now that's room service! <a href="http://travel.yahoo.com/hotelsearchpage;_ylc=X3oDMTFtaTIzNXVjBF9TAzk3NDA3NTg5BF9zAzI3MTk0ODEEcG9zAzIEc2VjA21haWx0YWdsaW5lBHNsawNxMS0wNw--
">Choose from over 150,000 hotels <br>in 45,000 destinations on Yahoo! Travel</a> to find your fit.