What is a graph?
A graph is an abstract data type to model data that contains objects which are in someway related to each other
What is an edge?
a line or edge describes the relationship between nodes.
What is a vertex?
A vertex, also node, is an entity object and it is comparable to a row in a SQL database.
Why would we want to use a graph database instead of a normal SQL database?
If you have to describe complex relationships this type of database is more efficient.