Neo4j is an open-source graph database, implemented in Java.The developers describe Neo4j as "embedded, disk-based, fully transactional Java persistence engine that stores data structured in graphs rather than in tables". Neo4j is the most popular graph database
In Neo4j, everything is stored in form of nodes and relationships. Each node and relationship can have any number of attributes. Both the nodes and relationship can be labelled. Labeling is useful, because you can narrow down your searching area using the labels. Neo4j suported node indexing.
What is Neo4j?
Neo4j is an open-source graph database supported by Neo Technology. Neo4j stores data in nodes and relationships with properties on both are connected by directed(-> or <- or -).
- intuitive, using a graph model for data representation
- reliable, with full ACID transactions
- durable and fast, using a custom disk-based, native storage engine
- massively scalable, up to several billion nodes/relationships/properties
- highly-available, when distributed across multiple machines
- expressive, with a powerful, human readable graph query language fast, with a powerful traversal framework for high-speed graph queries
- embeddable, with a few small jars
- simple, accessible by a convenient REST interface or an object-oriented Java API
What is a Graph Database?
A graph database stores data in a graph, the most generic of data structures, capable of elegantly representing any kind of data in a highly accessible way.
A graph having different records(nodes and relations), A node and relation have different properties, the relationship organizes the nodes