使用C＃创建neo4j数据库

Question

I'm trying to create a neo4j db using neo4jclient in C#... I want to create a constraint on a label property(ID), return the max value and then create the database.

var neotest = new GraphClient(new Uri("http://localhost:7474/db/data"), "username", "password");
        neotest.Connect();
        neotest.Cypher
            .CreateUniqueConstraint("n:Solution", "n.ID")
            .ExecuteWithoutResults();

string queryString = QueryHelper.GetQueryObject(Model);
var neotest1 = new GraphClient(new Uri("http://localhost:7474/db/data"),"username","password");
                neotest.Connect();
                neotest.Cypher
                    .Create("(n:Solution{" + queryString + "})")
                    .ExecuteWithoutResults();

The above code creates a neo4j database and adds constraint to the ID property as well.

However how do I get the max value of the ID property and increment it accordingly?

The cypher query is:

 match(n:Solution)return max(n.ID)  

But can't figure out how to implement it and use the max value. Please help.

Answer 1

The query to get the MAX is:

var query = client.Cypher
    .Match("(n:Solution)")
    .Return(() => Return.As<int>("MAX(n.ID)");

Just as a side note - you don't need to Connect to new instances of the client for each query, you can just do it all via one client instance.

In fact - looking at the code, you don't actually even use neotest1 as a variable at all.