It would be difficult to do as the criteria for “an individual exists” could vary. For example, you can’t simply check if the rdfs:label for a Student already exist as it’s possible that there are two students with the same name. You might need to check for a unique studentID, or a combination of first name, last name, and email address, or any other set of properties which will unique identify a Student.
If you’re storing Students in a file, why not just check if the student is in the file? On 9/6/16, 9:45 AM, "neha gupta" <[email protected]> wrote: >So it means there is no method which check if an individual exists or not? > >On Tue, Sep 6, 2016 at 4:55 AM, John A. Fereira <[email protected]> wrote: > >> You could run a query to get a resource with specific criteria (e.g. it >> has an rdfs:label which has the users name). If you get a result, replace >> the triple which has their GPS, otherwise create a new Student. >> >> -----Original Message----- >> From: neha gupta [mailto:[email protected]] >> Sent: Tuesday, September 6, 2016 3:13 AM >> To: [email protected] >> Subject: Creating individuals if not already exists >> >> I have created Students individuals in Jena and stored them in a file. >> Every time students login, updates their information like GPA and updates >> stored in the file. >> Student.createIndividual(ns, stdName); >> >> With this statement, suppose a student Neha is created with her >> information in the file. Next time, she login, again a new instance will be >> created when the application executes *Student.createIndividual(ns, >> stdName);?* >> >> *Is there any condition which states if the individual not already exists, >> create it otherwise skip createIndividual statement?* >>
