O: Deleting Nodes and Relationships


Deleting nodes and relationships, using the DELETE clause in Cypher, is an important operation in managing the graph database.

Deleting Nodes

The general syntax for deleting a node is:

MATCH (n:NodeLabel {propertyName: propertyValue})
DELETE n

Where:

  • n is the node variable
  • NodeLabel is the label assigned to the node
  • propertyName is the property name
  • propertyValue is the value assigned to the property
  • DELETE is used to delete the node
  • MATCH is used to find the node to delete
  • ... represents additional properties

Example: Deleting a Student Node

MATCH (s:Student {studentID: '123456'})
DELETE s

Deleting Relationships

The general syntax for deleting a relationship is:

MATCH (n1:NodeLabel1)-[r:RELATIONSHIP_TYPE]->(n2:NodeLabel2)
DELETE r

Where:

  • n1 and n2 are the node variables
  • NodeLabel1 and NodeLabel2 are the labels assigned to the nodes
  • r is the relationship variable
  • RELATIONSHIP_TYPE is the type of relationship
  • DELETE is used to delete the relationship
  • MATCH is used to find the relationship to delete
  • ... represents additional properties

Example: Deleting a Relationship Between a Student and an Activity

MATCH (s:Student {studentID: '123456'})-[r:ATTENDS]->(a:Activity {activityID: '789'})
DELETE r