Read with a Cypher query
|
All the examples in this page assume that the |
If you need more flexibility, you can use the query option to run a custom Cypher® query.
The query must include a RETURN clause.
With stored procedures, you need to include a YIELD clause before RETURN.
query option exampleval query = """
MATCH (n:Person)
WITH n
LIMIT 2
RETURN id(n) AS id, n.name AS name
"""
spark.read.format("org.neo4j.spark.DataSource")
.option("query", query)
.load()
.show()
| id | name |
|---|---|
0 |
John Doe |
1 |
Jane Doe |
DataFrame columns
The structure of the result DataFrame is defined by the query itself. See the Schema inference page for more details.
This option is best suited when you return individual properties rather than graph entities (nodes, relationships, paths). Returning a graph entity, anyway, does not cause an error.
| Recommended | Not recommended |
|---|---|
MATCH (p:Person) RETURN id(p) AS id, p.name AS name |
MATCH (p:Person) RETURN p |
|
If you need to return a graph entity, use the |
Limit the results
The connector uses SKIP and LIMIT internally to support partitioned reads; as a result, SKIP and LIMIT clauses are not allowed in a custom Cypher query.
Attempts to do this will cause execution errors.
A possible workaround is to use SKIP and LIMIT before the RETURN clause.
For example, the following query fails:
MATCH (p:Person)
RETURN p.name AS name
ORDER BY name
LIMIT 10
The query can be rewritten with LIMIT before the RETURN to complete successfully:
MATCH (p:Person)
WITH p.name AS name
ORDER BY name
LIMIT 10
RETURN p.name
|
When you rewrite a query, make sure the new query is equivalent to your original query so that the result is the same. |
You can also use the query.count option instead of rewriting your query.
See the Spark optimizations page for more details.
The script option
The script option allows to run a sequence of Cypher queries before executing the read operation.
The result of the script can be used in a subsequent query, for example to inject query parameters.
script and query exampleval script = "RETURN 'foo' AS val"
val query = """
UNWIND range(1, 2) as id
RETURN id AS val, scriptResult[0].val AS script
"""
spark.read.format("org.neo4j.spark.DataSource")
.option("script", script)
.option("query", query)
.load()
.show()
| val | script |
|---|---|
1 |
foo |
2 |
foo |