7.5. Parameters
Cypher supports querying with parameters. This means developers don’t have to resort to string building to create a query. In addition to that, it also makes caching of execution plans much easier for Cypher.
Parameters can be used for literals and expressions in the WHERE
clause, for the index value in the START
clause, index queries, and finally for node/relationship ids.
Parameters can not be used as for property names, relationship types and labels, since these patterns are part of the query structure that is compiled into a query plan.
Accepted names for parameters are letters and numbers, and any combination of these.
For details on using parameters via the Neo4j REST API, see Section 19.1, “Transactional Cypher HTTP endpoint”. For details on parameters when using the Neo4j embedded Java API, see Section 32.13, “Query Parameters”.
Below follows a comprehensive set of examples of parameter usage. The parameters are given as JSON here. Exactly how to submit them depends on the driver in use.
String literal
Parameters.
{ "name" : "Johan" }
Query.
MATCH (n) WHERE n.name = { name } RETURN n
Regular expression
Parameters.
{ "regex" : ".*h.*" }
Query.
MATCH (n) WHERE n.name =~ { regex } RETURN n.name
Create node with properties
Parameters.
{ "props" : { "position" : "Developer", "name" : "Andres" } }
Query.
CREATE ({ props })
Create multiple nodes with properties
Parameters.
{ "props" : [ { "position" : "Developer", "awesome" : true, "name" : "Andres" }, { "position" : "Developer", "name" : "Michael", "children" : 3 } ] }
Query.
CREATE (n:Person { props }) RETURN n
Setting all properties on node
Note that this will replace all the current properties.
Parameters.
{ "props" : { "position" : "Developer", "name" : "Andres" } }
Query.
MATCH (n) WHERE n.name='Michaela' SET n = { props }
SKIP and LIMIT
Parameters.
{ "s" : 1, "l" : 1 }
Query.
MATCH (n) RETURN n.name SKIP { s } LIMIT { l }
Node id
Parameters.
{ "id" : 0 }
Query.
START n=node({ id }) RETURN n.name
Multiple node ids
Parameters.
{ "id" : [ 0, 1, 2 ] }
Query.
START n=node({ id }) RETURN n.name
Index value (legacy indexes)
Parameters.
{ "value" : "Michaela" }
Query.
START n=node:people(name = { value }) RETURN n
Index query (legacy indexes)
Parameters.
{ "query" : "name:Andreas" }
Query.
START n=node:people({ query }) RETURN n