Recently, the company wants to make a function of knowledge graph, including nodes and relations. Actually, this is a graph in terms of data structure, and we need a database that supports graph structure.

So let’s look at the last one

Command usage of Neo4j

Nodes:

To query all nodes, run MATCH (n) RETURN n

Run the MATCH (n) detach delete n command to delete all nodes

Query nodes based on their IDS: MATCH (n) WHERE ID (n)=251 RETURN n

MATCH (n) WHERE id(n)<>5 and n.name =~ ‘.* Ann.*’ RETURN n

Add node: CREATE (n: writer {name:’ lu Xun ‘}) RETURN n;

Detach delete n Detach delete n Detach delete n Detach delete n Detach delete n detach delete n

Match (b) where ID (b)= 9 Set B: writer, B.name = ‘Kevinnn’ return b

Relationship:

MATCH (c: writer) WITH C OPTIONAL MATCH (c)-[r]-() RETURN c, r

Match (a),(b) where id(a)=9 and id(b)=5 merge (a) -[:test] -> (b)

Delete a relationship based on the ID: match(a)-[r]-(b) where ID (r)=1103 delete r

Find all relationships starting from that ID based on that ID

MATCH (c)-[r]->(d) where id(c) = 5 RETURN r

Delete all relationships starting with c:

MATCH (c)-[r]->(d) where id(c) = 9 delete r