Parameters

A common challenge with dynamic queries is keeping track of parameters. To solve this, you can use the class Param to create Cypher^® Builder parameters.

Parameters behave similarly to variables, however, they contain a defined value that will automatically be returned as part of the parameters when the .build() method is called. For example:

const movie = new Cypher.Node({ labels: ["Movie"] });
const titleProp = movie.property(movie);

const query = new Cypher.Match(movie).where(Cypher.eq(titleProp, new Cypher.Param("The Matrix")));

const { cypher, params } = query.build();

Returns the following Cypher:

MATCH (this0:Movie)
WHERE this0[this0] = $param0

And the following parameters object:

{
    param0: "The Matrix"
}

Parameters can also be reused, like variables:

const movie = new Cypher.Node({ labels: ["Movie"] });
const titleProp = movie.property(movie);
const titleParam = new Cypher.Param("The Matrix");

const query = new Cypher.Match(movie).where(Cypher.eq(titleProp, titleParam)).return(titleParam);

const {cypher, params} = query.build();

Cypher

MATCH (this0:Movie)
WHERE this0[this0] = $param0
RETURN this0, $param0

Params

{
    param0: "The Matrix"
}

In such cases, Cypher Builder provides a name to the parameter and correctly links it to the Param object.

Note that if two instances of Param are used, then two separate parameters should be returned, regardless of the value. For example:

const movie = new Cypher.Node({ labels: ["Movie"] });
const titleProp = movie.property(movie);
const titleParam1 = new Cypher.Param("The Matrix");
const titleParam2 = new Cypher.Param("The Matrix")

const query = new Cypher.Match(movie).where(Cypher.eq(titleProp, titleParam1)).return(titleParam2);

const {cypher, params} = query.build();

Cypher

MATCH (this0:Movie)
WHERE this0[this0] = $param0
RETURN this0, $param0

Params

{
    param0: "The Matrix"
}