Feature #105

Duplicate variables in BGPs can be handled in algebra

Added by Paula Gearon over 9 years ago. Updated over 9 years ago.

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 over 9 years ago

  • Status changed from New to Closed
  • Resolution set to duplicate

See ticket #120

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