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I want to add a relationship between two nodes, but only if the relationship does not exist. For example:
The Relationship between node1 and node2 currently exists with these properties: time:41221323,link:www.google.com
I am trying to add a relationship with different properties for example:
time:5344241,link:www.google.com
In this case i want to keep the original properties on the relationship.
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In Neo4j to create relationship between nodes you have to use the CREATE statement like we used to create nodes. lets create relation between two already created nodes.
An OPTIONAL MATCH matches patterns against your graph database, just like a MATCH does. The difference is that if no matches are found, OPTIONAL MATCH will use a null for missing parts of the pattern. OPTIONAL MATCH could be considered the Cypher equivalent of the outer join in SQL.
Relationships always has a direction (one direction). Relationships must have a type (one type) to define (classify) what type of relationship they are. Nodes and relationships can have properties (key-value pairs), which further describe them.
You can use the below CQL query:
MATCH(a: startNodeLabel {attributes to match start node}) MATCH(m:endNodeLabel {attributes to match end node}) MERGE(a)-[:relationshipName]->(m)
The above merge statement creates relation between nodes a and m if there is no existing relationship between a and m.
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