A form of non-relational database where links between entries are first-class citizens.
Graph databases are a Types of Non-relational Databases architectures in such a way where the relations (links) that exist between entries are just as important as the links themselves. In Graph parlance, entries are “Nodes”, relationships are “Edges”, and both kinds can have “Properties”.
Popular Graph Databases include Neo4j, Amazon Neptune, and others.
Graph Databases don’t use SQL, but instead query languages like GraphQL, SPARQL or Cypher.
Graphs are employed by Social Networks (where friends of friends is a common scheme) and Recommendation Engines (where “if you like X you might like Y” is based on how those things are related).