How to make a graphql schema with @cypher directive

[kangwachimba7]

Hello everyone I believe I have a simple problem but I can’t seem to solve it. I am using Graphql with Neo4j. I want to simply count relationships and put that capability in my graphql schema using the “CALL graphql.idl()” procedure and the “@cypher”directive,my code is as follows

CALL graphql.idl(
"
type User{
userSocialFollowsCount:@cypher(statement:”MATCH (u:User)-[:FOLLOWS_ON_SOCIALS]->(o:User) WITH u,count(o) as rels WHERE rels > 1 RETURN rels”)
}
"
)

``

Iv also tried this example from the internet 

CALL graphql.idl("

type User{

degree: Int @cypher(statement: "RETURN SIZE((this)-->())")

}

"
)

I am getting a syntax error in the Neo4j browser but I don’t understand where exactly the problem is.. I want to update my schema to be able to count relationships using the procedure.

I having installed the FULL APOC manually to the Graphene Database & they have confirmed it is installed okay ... I checked the version & it is compatible with the instance 


What am I doing wrong? How do you use the @cypher directive in a graphql schema with the “CALL graphql.idl()” procedure to update the schema? I want to do it automatically using the procedure but I seem to be missing something.. thanks 🙏

[MuddyBootsCode]

I think the answer to this question will give you a base to solve yours. Give it a shot:

Count relationship on each nodes Cypher

I have nodes with one of the properties called "Model". If I have node names as a,b,c,d,e etc, a.Model="1" b.Model="2" c.Model="3" d.Model="1" etc I want to ask a query : "For a particular Model, return the count of relationships for each individual nodes " If i ask for Model=1 , it should give me the count of relationships for each distinct node under Model 1. need results like below for Model="1" a---> count of relationships for a d---> count of relationships for d

also: Even those this is an older article it's got some good info:

PHPFog.com – 25 Jan 21

Counting Relationships in Neo4j - PHPFog.com

When working with different graphs in Neo4j, it is often important to count the number of relationships between different nodes. Below are examples of common relationship counting tasks. The data for these examples can be found here and the script to...

Est. reading time: 2 minutes

[kangwachimba7]

@MuddyBootsCode

Thanks for the reference well explained and simplified but I am getting the following exception

"

Neo.ClientError.Procedure.ProcedureCallFailed

Failed to invoke procedure graphql.idl: Caused by: java.lang.RuntimeException: Error parsing IDL expected {'[', 'fragment', 'query', 'mutation', 'subscription', 'schema', 'scalar', 'type', 'interface', 'implements', 'enum', 'union', 'input', 'extend', 'directive', NAME} got '@' line 20 column 23
"

[MuddyBootsCode]

Ok can you please show me the query you're using in your schema please?

[kangwachimba7]

@MuddyBootsCode

graphql.idl(“      
type User {       
userFollows:@cypher(statement:”MATCH (n)-[r:User_Follows]->() RETURN COUNT(r)”)
}
“)

[MuddyBootsCode]

This is how I implemented it in my own:

wellCount: Int @cypher (
statement: "MATCH (this)<-[r:DRILLED_ON]-(:Well) with this, count(r) as rel_cnt return rel_cnt"
)

[kangwachimba7]

@MuddyBootsCode

I have re-adapted it to:

graphql.idl(“      
type User {       
followsCount:Int @cypher (
statement: "MATCH (this)<-[r:FOLLOWS_ON_SOCIALS]-(:User) with this, count(r) as rel_cnt return rel_cnt"
)
}
“)

I am getting the following error

Neo.ClientError.Statement.SyntaxError

Invalid input 'M': expected whitespace, '.', node labels, '[', "=~", IN, STARTS, ENDS, CONTAINS, IS, '^', '*', '/', '%', '+', '-', '=', '~', "<>", "!=", '<', '>', "<=", ">=", AND, XOR, OR, ',' or ')' (line 20, column 13 (offset: 574)) "statement: "MATCH (this)<-[r:FOLLOWS_ON_SOCIALS]-(:User) with this, count(r) as rel_cnt return rel_cnt""

[MuddyBootsCode]

I’m not super sure how your schema is constructed but it looks like it’s not quite right. Is it in a schema.graphql file?

[kangwachimba7]

@MuddyBootsCode

when I run CALL graphql.schema() I get a schema and the schema generation command CALL graphql.idl() runs when I omit the field with the "@cypher" directive on the relevant Node type

[MuddyBootsCode]

You might try it the way that the project is set up on the GRANDstack example and have it in a schema.graphql file. It seems that the graphql.idl isn't playing well with Neo4j.

[kangwachimba7]

@MuddyBootsCode

Thanks

btw How do you edit the graphql.schema file directly?

[MuddyBootsCode]

Here's a link to a project that @William_Lyon is working on currently that has a great video series along with it. https://github.com/johnymontana/willow-grandstack/tree/master/api/src In it you can see how the schema.graphql file is set up and used.

Sorry I mean use the schema.graphql file not the graphql-schema.js

[kangwachimba7]

thanks but I am using the plugin on desktop and I think thats a Java/kotlin kind of set up... its just not working the graphql plugin on desktop with cypher

[kangwachimba7 · Accepted solution]

I have found the solution from the Github issue I was using double quotes throughout instead of single quotes to inclose the schema command

[kangwachimba7]

I have even downgraded and re-installed APOC .. still not working

[MuddyBootsCode]

Glad you got it figured out. Though the original question was about how to handle counting relationships.