Constant GRAPHQL_SCHEMA 

pub const GRAPHQL_SCHEMA: &str = r#"
    type Node {
        id: ID!
        data: String!
        createdAt: String!
    }

    type GraphEdge {
        from: ID!
        to: ID!
        label: String!
        properties: String!
    }

    type TraversalResult {
        node: Node!
        depth: Int!
    }

    type SearchResult {
        node: Node!
        score: Float!
    }

    input CreateNodeInput {
        data: String!
    }

    input UpdateNodeInput {
        id: ID!
        data: String!
    }

    input CreateEdgeInput {
        from: ID!
        to: ID!
        label: String!
        properties: String!
    }

    input TraverseInput {
        from: ID!
        labels: [String!]
        maxDepth: Int!
        asOf: String
    }

    type Query {
        node(id: ID!): Node
        nodeAt(id: ID!, asOf: String!): Node
        traverse(input: TraverseInput!): [TraversalResult!]!
        search(query: String!): [SearchResult!]!
    }

    type Mutation {
        createNode(input: CreateNodeInput!): Node!
        updateNode(input: UpdateNodeInput!): Node!
        createEdge(input: CreateEdgeInput!): GraphEdge!
    }
"#;

GraphQL SDL (Schema Definition Language)