Add several maps to the result.
Add several maps to the result.
Map to add
Add one mapping to the result line.
Merge two reuslts as one.
Select the required variable fields of the result, remove mapping which key is not in the project field.
Return a new result for the required variable fields.
Return a new result for the required variable fields. Compare to method project, this method will not change this result, but return a new one.
Remove a set of variables from the result line.
Remove one mapping from the result line.
A class represent one result for SPARQL query.
Attribute of the key and value