Parameters

This page describes parameterized querying.

Introduction

Cypher® supports querying with parameters. A parameterized query is a query in which placeholders are used for parameters and the parameter values are supplied at execution time. This means developers do not have to resort to string building to create a query. Additionally, parameters make caching of execution plans much easier for Cypher, thus leading to faster query execution times.

Parameters can be used for:

Parameters cannot be used for the following constructs, as these form part of the query structure that is compiled into a query plan:

  • Property keys; MATCH (n) WHERE n.$param = 'something' is invalid.

  • Relationship types; MATCH (n)-[:$param]→(m) is invalid.

  • Node labels; MATCH (n:$param) is invalid.

Parameters may consist of letters and numbers, and any combination of these, but cannot start with a number or a currency symbol.

Setting parameters when running a query is dependent on the client environment. For example:

We provide below a comprehensive list of examples of parameter usage. In these examples, parameters are given in JSON; the exact manner in which they are to be submitted depends upon the driver being used.

Auto-parameterization

From Neo4j 5 onwards, even when a query is partially parameterized, Cypher will try to infer parameters anyway. Each literal in the query is replaced with a parameter. This increases the re-usability of the computed plan for queries that are identical except for the literals. It is not recommended to rely on this behavior - users should rather use parameters where they think it is appropriate.

String literal

Parameters
{
  "name": "Johan"
}
Query
MATCH (n:Person)
WHERE n.name = $name
RETURN n

You can use parameters in this syntax as well:

Parameters
{
  "name": "Johan"
}
Query
MATCH (n:Person {name: $name})
RETURN n

Regular expression

Parameters
{
  "regex": ".*h.*"
}
Query
MATCH (n:Person)
WHERE n.name =~ $regex
RETURN n.name

Case-sensitive STRING pattern matching

Parameters
{
  "name": "Michael"
}
Query
MATCH (n:Person)
WHERE n.name STARTS WITH $name
RETURN n.name

Create node with properties

Parameters
{
  "props": {
    "name": "Andy",
    "position": "Developer"
  }
}
Query
CREATE ($props)

Create multiple nodes with properties

Parameters
{
  "props": [ {
    "awesome": true,
    "name": "Andy",
    "position": "Developer"
  }, {
    "children": 3,
    "name": "Michael",
    "position": "Developer"
  } ]
}
Query
UNWIND $props AS properties
CREATE (n:Person)
SET n = properties
RETURN n

Setting all properties on a node

Note that this will replace all the current properties.

Parameters
{
  "props": {
    "name": "Andy",
    "position": "Developer"
  }
}
Query
MATCH (n:Person)
WHERE n.name = 'Michaela'
SET n = $props

SKIP and LIMIT

Parameters
{
  "s": 1,
  "l": 1
}
Query
MATCH (n:Person)
RETURN n.name
SKIP $s
LIMIT $l

Node id

Parameters
{
  "id" : "4:1fd57deb-355d-47bb-a80a-d39ac2d2bcdb:0"
}
Query
MATCH (n)
WHERE elementId(n) = $id
RETURN n.name

Multiple node ids

Parameters
{
  "ids" : [ "4:1fd57deb-355d-47bb-a80a-d39ac2d2bcdb:0", "4:1fd57deb-355d-47bb-a80a-d39ac2d2bcdb:1" ]
}
Query
MATCH (n)
WHERE elementId(n) IN $ids
RETURN n.name

Calling procedures

Parameters
{
  "indexname" : "My_index"
}
Query
CALL db.resampleIndex($indexname)