Fig. 2From: Graph4Med: a web application and a graph database for visualizing and analyzing medical databasesSchema graph. The constructed and compressed schema graph \(\textbf{RG}\) which is split into two parts \(\mathbf {RG_1} \cup \mathbf {RG_2}\) (left and right, respectively). Nodes with a thick outline represent PK attributes. Sinks are colored green and sources are colored redBack to article page