Logical Operators

Logical plans of HeFQUIN are FedQPL expressions [1]. Hence, the logical operators that HeFQUIN uses are the FedQPL operators. The main interface for these operators is called LogicalOperator. Their implementations can be found in the se.liu.ida.hefquin.engine.queryplan.logical.impl package and include:

Nullary Operators

• req

Unary Operators

• tpAdd
• tpOptAdd
• bgpAdd
• bgpOptAdd
• gpAdd
• gpOptAdd
• filter
• g2l
• l2g

Binary Operators

• join
• rightjoin
• union

N-ary Operators

• mj
• mlj
• mu

[1] Sijin Cheng and Olaf Hartig: FedQPL: A Language for Logical Query Plans over Heterogeneous Federations of RDF Data Sources. In Proceedings of the 22nd International Conference on Information Integration and Web-based Applications & Services (iiWAS), 2020.