CODEWITHSUNDEEP
neo4j
Deeswoc
Deeswoc

Reputation: 180

How do you set objects as parameters from neo4j desktop

I can set parameters as arrays and other data types with the syntax

:param x => ["some Data", "other data"

:param y => 5

:param z => "Hello"

But doing this yields an error

:param someObject => {
   data:"something"
   moreData:"something else"
}

Error:

Invalid input 'd': expected whitespace or a label name

I've been unable to find any documentation that goes into parameters in depth so I have no clue what the syntax should be here. It seems to expect a query when I use curly braces

Upvotes: 0

Views: 504

Answers (3)

Deeswoc
Deeswoc

Reputation: 180

There isn't any documentation on the website but there is very helpful documentation inside when using the :help command in the browser. Specifically :help params

cybersam's answer works but needs but doesn't fully explain what's going on and is based on the older syntax. The right hand of => is evaluated as Cypher and an implicit RETURNis placed in front. Therefore:

:param x => 4

can be expressed explicitly as

:param [{x}] => { RETURN 4 as x }

When explicitly setting a param the express on the right has to be wrapped in{} with RETURN explicitly placed in front of the expression inside. This was the issue with the query in the question. Nothing is returned inside of {} so an error gets thrown.

Additionally the results have to be destructured in this format [{x, y, z}] and I haven't confirmed this but I suspect its because the syntax to set params can return mutliple results as with any regular query.

:param [{a, b, c}] => {match (n) where id(n) = 31 return 4 as a, 5 as b, n as c}

Upvotes: 0

cybersam
cybersam

Reputation: 67019

For some reason, the older :param syntax is no longer documented, even though it is still supported in neo4j 4.1 (by the cypher-shell tool and the neo4j browser). That older syntax supports the creation of parameters with map values in a very straightforward way.

For example, this will create a someObject parameter with your desired value:

:param someObject: {data: "something", moreData: "something else"}

Upvotes: 3

Alexander Makarov
Alexander Makarov

Reputation: 886

Good day, What are you intent to do with that param? In general, params should be a valid JSON, so the easiest way to fix above sample is to embrace keys with double quotes and ebrace the object by single quotes: :param someObject => '{ "data": "something", "moreData": "something else" }'

Upvotes: 0

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