Glossary

edge-disjoint path cover

A covering of a graph with a set of paths, which intersect each other only at their end points.

exhaustive graph rewrite system (XGRS)

A variant of graph rewrite systems on relational graphs, i.e. on graphs with one edge of a certain label between two nodes. Each rule adds an edge but no node to a termination subgraph, thus the systems terminate

order

A characteristic feature of a rule group or a GRS: the maximal number of root nodes of left hand sides.

order loop

A loop in the generated code which traverses a domain of a root node of some left hand sides.

order loop node

A node instantiated in an order loop.

nested-loop join

A code generation method from and relational algebra to evaluate relational queries.

node

A variable which denotes a node of the rule test graph

pattern variable

A variable set in a pattern. May be a node or a scalar variable.

rule test

A left hand side of a graph rewrite system and a rule body of a -query.

rule test graph, RTG

A left hand side of a graph rewrite system consists of a graph, the rule test graph.

rule transformation

A right hand side of a graph rewrite system.

scalar variable

A variable with scalar value. No rule test graph node.