Analyze the core technical principle of NEO4J database

NEO4J is a graphical database management system. Its core technical principles involve multiple aspects, such as graphic models, data storage, query processing and index. First, NEO4J uses graphics models to represent and store data.The graphic model consists of nodes and relationships. Each node can have attributes, while the relationship indicates the connection between nodes.The graphic model is very suitable for the relationship between complex entities and entities, which can help us better understand and analyze data. Secondly, the data storage of NEO4J is based on a data structure called "attribute map".The attribute map combines the graphic model with the key value to the storage structure in order to store and retrieve graphical data efficiently.Each node and relationship can include attributes. These attributes are stored as key values pairs, and they can be indexed and queried according to the attributes. The query processing is another core technical principle of Neo4J.Neo4J provides a query language called CyPher, which uses syntax similar to SQL to query graphic data.For complex queries, Neo4J uses an efficient graphics traversal calendar algorithm to find nodes and relationships that meet conditions. In addition, NEO4J also supports attribute -based indexes, which can quickly locate data according to the attribute value of the node or relationship.Index can significantly improve the query performance, and can meet different query needs by configuring different index strategies. The following is a sample code and related configuration description of NEO4J: // Import the NEO4J library import org.neo4j.driver.*; // Establish a connection with the database Driver driver = GraphDatabase.driver("bolt://localhost:7687", AuthTokens.basic("neo4j", "password")); // Execute the query in the affairs try (Session session = driver.session()) { Result result = session.run("MATCH (n) RETURN n LIMIT 5"); while (result.hasNext()) { Record record = result.next(); // Process query results System.out.println(record.get("n").asNode().get("name").asString()); } } // Turn off the connection driver.close(); The above code demonstrates the basic usage of NEO4J.First of all, we need to introduce NEO4J -related libraries.Then build a connection with the database by creating a driver.In this example, we use the local connection, the host is called "LocalHost", the port number is 7687, the user name is "Neo4J", and the password is "Password". After the connection is established, we can perform query in one transaction.In this example, we use CyPher to query the language matching all nodes and return the first five records.Then, we traverse the query results and print the name attribute of each node. Finally, we turn off the connection and release resources. By understanding the core technical principles of NEO4J and some example code and related configuration, we can better understand and apply this powerful graphical database management system.