search

kg-construct / rml-lv

Specification repository for logical views in RML.
https://kg-construct.github.io/rml-lv/dev.html
3 stars 3 forks source link

Order of execution of logical view joins #37

Open elsdvlee opened 3 months ago

elsdvlee commented 3 months ago

If there is more than one join, what is the order of execution? (Remark of @pmaria moved from spec to issues)

elsdvlee commented 3 months ago

The logical view joins are more limited than SQL joins. The join conditions are linked to one join and only involve an equal condition on references from the child logical view and compared to references from the parent logical view. The child logical view always remains the same and is always are the left side of the join. And only left (outer) joins and inner joins are defined. Therefore I think that execution order doesn't matter. @pmaria @tirrolo Can you contribute to the solution for this issue?