Reactome graph database: Efficient access to complex pathway data
Fig 1
A simplified example where reactions only contain reactants and products represented by the class PhysicalEntity.
(a) In the relational use case, two junction tables are required to model these many-to-many relationships (b) SQL query used to retrieve input and output entities of a given reaction where two join operations are needed per junction table. (c) The same reaction modelled as a graph. The reaction (green node) contains named outgoing relationships to corresponding input and output entities (purple nodes). (d) The same query written in Cypher, in a shorter but more intuitive manner.