Function QueryGraph_MergeGraphs

src/graph/query_graph.c:442–474

}

void QueryGraph_MergeGraphs
(
	QueryGraph *to,
	QueryGraph *from
) {
	uint node_count = QueryGraph_NodeCount(from);
	uint edge_count = QueryGraph_EdgeCount(from);

	for(uint i = 0; i < node_count; i++) {
		QGNode *n = from->nodes[i];
		// if the entity already exists in the "to" graph, do nothing
		// we could have more complex logic to merge entity data, but this is not
		// currently necessary as this logic only benefits toString calls like EXPLAIN
		if(QueryGraph_GetNodeByAlias(to, n->alias)) continue;
		// new entity, clone and add it
		QueryGraph_AddNode(to, QGNode_Clone(n));
	}

	for(uint i = 0; i < edge_count; i++) {
		QGEdge *e = from->edges[i];
		// if the entity already exists in the "to" graph, do nothing
		// we could have more complex logic to merge entity data, but this is not
		// currently necessary as this logic only benefits toString calls like EXPLAIN
		if(QueryGraph_GetEdgeByAlias(to, e->alias)) continue;

		// retrieve the edge's endpoints in the "to" graph
		QGNode *src = QueryGraph_GetNodeByAlias(to, e->src->alias);
		QGNode *dest = QueryGraph_GetNodeByAlias(to, e->dest->alias);
		// clone and add the unmatched edge
		QGEdge *clone_edge = QGEdge_Clone(e);
		QueryGraph_ConnectNodes(to, src, dest, clone_edge);
	}
}

QGNode *QueryGraph_GetNodeByAlias
(