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Import data

For adding new data, you can use the following clauses.

  • CREATE, for creating new nodes and relationships.
  • SET, for adding new or updating existing labels and properties.

You can still use the RETURN clause to produce results after writing, but it is not mandatory.

Details on which kind of data can be stored in Memgraph can be found in the Storage chapter.

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Indexing can increase performance when executing queries. Please take a look at our documentation on indexing for more details.

CREATE​

This clause is used to add new nodes and relationships to the database. The creation is done by providing a pattern, similarly to MATCH clause.

For example, use this query to create two new nodes connected with a new relationship.

CREATE (node2)-[:RELATIONSHIP_TYPE]->(node2);

Labels and properties can be set during creation using the same syntax as in MATCH patterns. For example, creating a node with a label and a property:

CREATE (node:Label {property: 'my property value'});

Additional information on CREATE is available here.

WITH​

The write part of the query cannot be simply followed by another read part. To combine them, the WITH clause must be used. The names this clause establishes are transferred from one part to another.

For example, creating a node and finding all nodes with the same property.

CREATE (node {property: 42}) WITH node.property AS propValue
MATCH (n {property: propValue}) RETURN n;

Note that the node is not visible after WITH, since only node.property was carried over.

This clause behaves very much like RETURN, so you should refer to features of RETURN.

MERGE​

The MERGE clause is used to ensure that a pattern you are looking for exists in the database. This means that it will be created if the pattern is not found. In a way, this clause is like a combination of MATCH and CREATE.

For example, ensure that a person has at least one friend:

MATCH (n:Person) MERGE (n)-[:FRIENDS_WITH]->(m);

The clause also provides additional features for updating the values depending on whether the pattern was created or matched. This is achieved with ON CREATE and ON MATCH sub clauses.

For example, set different properties depending on what MERGE did:

MATCH (n:Person) MERGE (n)-[:FRIENDS_WITH]->(m)
ON CREATE SET m.prop = "created" ON MATCH SET m.prop = "existed";

For more details, check out this guide.

Import existing data from CSV​

Using CSV files is just one of the ways to import your data into Memgraph. The LOAD CSV clause enables you to load and use data from a CSV file. Memgraph supports the Excel CSV dialect, as it's the most commonly used one. For the syntax of the clause, please check the LOAD CSV page in the Cypher manual.