Feature #105
Duplicate variables in BGPs can be handled in algebra
Status:  Closed  Start date:  

Priority:  Normal  Due date:  
Assignee:  Paula Gearon  % Done:  0% 

Category:  Mulgara  
Target version:  SPARQL Query Engine  
Resolution:  duplicate 
Description
Instead, successive instances of the same variable should be renamed, and the constraint should be conjoined with itself with the repeated variables rotated around. e.g. for 2 variables: {?x ?x ?y} becomes: {?x ?x2 ?y} AND {?x2 ?x ?y} {?x ?y ?x} becomes: {?x ?y ?x2} AND {?x2 ?y ?x} {?y ?x ?x} becomes: {?y ?x ?x2} AND {?y ?x2 ?x} and for 3 variables: {?x ?x ?x} becomes: {?x ?x2 ?x3} AND {?x3 ?x ?x2} AND {?x2 ?x3 ?x} The values of ?x2 and ?x3 can always be ignored since they are identical to ?x.
History
Updated by Paula Gearon about 10 years ago
 Status changed from New to Closed
 Resolution set to duplicate
See ticket #120