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Neo4j with the .NET driver

Uses Neo4j.Driver 6.4 on .NET 10. The code is an ordinary application for the original database; nothing in it knows about MachNoSQL.

The only change

Section titled “The only change”
neo4j://neo4j.example.com:7687
neo4j://machnosql.example.com:7687

The address comes from the environment variable NEO4J_URI, so switching to MachNoSQL changes configuration only.

Run

Section titled “Run”
Terminal window
export NEO4J_URI='neo4j://machnosql.example.com:7687'
dotnet run

Credentials come from NEO4J_USERNAME and NEO4J_PASSWORD.

Source

Section titled “Source”

The program as it is kept and tested in the Mach Database NoSQL repository; highlighted lines read the connection setting.

Program.cs
// Friends of friends on Neo4j, unchanged on MachNoSQL.
using Neo4j.Driver;


await using var driver = GraphDatabase.Driver(
    Environment.GetEnvironmentVariable("NEO4J_URI"),
    AuthTokens.Basic(Environment.GetEnvironmentVariable("NEO4J_USERNAME"), Environment.GetEnvironmentVariable("NEO4J_PASSWORD")));
await driver.VerifyConnectivityAsync();


var pairs = new[] { new[] { "ada", "grace" }, new[] { "grace", "linus" }, new[] { "grace", "margaret" }, new[] { "linus", "ken" } };
await driver.ExecutableQuery("UNWIND $pairs AS pair MERGE (a:Person {name: pair[0]}) MERGE (b:Person {name: pair[1]}) MERGE (a)-[:KNOWS]->(b)")
    .WithParameters(new { pairs })
    .ExecuteAsync();


var result = await driver.ExecutableQuery("MATCH (p:Person {name: $name})-[:KNOWS]->()-[:KNOWS]->(fof) WHERE fof <> p RETURN DISTINCT fof.name AS name ORDER BY name")
    .WithParameters(new { name = "ada" })
    .ExecuteAsync();
foreach (var record in result.Result)
{
    Console.WriteLine(record["name"].As<string>());
}
Example.csproj
<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net10.0</TargetFramework>
    <Nullable>enable</Nullable>
    <ImplicitUsings>enable</ImplicitUsings>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="Neo4j.Driver" Version="6.4.0" />
  </ItemGroup>
</Project>