GQL Execution

This section introduces the Gql() and GqlStream() methods on a Connection object for querying the database using GQL.

Each example focuses solely on the method's usage. For a complete code example, please refer to the full example.

NOTE

GQL (Graph Query Language) is the ISO-standard query language for graph databases. For detailed information on GQL, refer to the documentation.

Gql()

Executes a GQL query on the current graphset or the database and returns the result.

Parameters:

• string: The GQL query to be executed.
• RequestConfig (Optional): Configuration settings for the request.

Returns:

• Response: Result of the request.

C#
// Retrieves 5 movie nodes in graphset 'miniCircle' and prints their information

RequestConfig requestConfig = new RequestConfig() { Graph = "miniCircle", UseMaster = true };

var res = await ultipa.Gql("MATCH (n:movie) RETURN n LIMIT 5", requestConfig);
var nodeList = res?.Alias("n")?.AsNodes();
foreach (var node in nodeList)
{
    Console.WriteLine(node.Values.GetValueOrDefault("name"));
}

Output
The Shawshank Redemption
Farewell My Concubine
Léon: The Professional
Titanic
Life is Beautiful

For more examples, please refer to Types Mapping Ultipa and C#.

GqlStream()

Executes a GQL query on the current graphset or the database and returns the result incrementally, allowing handling of large datasets without loading everything into memory at once.

Parameters:

• string: The GQL query to be executed.
• QueryResponseStream: Listener for the streaming process.
• RequestConfig (Optional): Configuration settings for the request.

Returns:

• void

C#
// Retrieves all 1-step paths in graphset 'miniCircle'
RequestConfig requestConfig = new RequestConfig() { Graph = "miniCircle", UseMaster = true };

var count = 0;
await ultipa.GqlStream(
    "MATCH p = ()-[]-() RETURN p",
    new QueryResponseStream()
    {
        OnStart = () => Console.WriteLine("Start"),
        OnData = (
            resp =>
            {
                if (resp.Status.ErrorCode != ErrorCode.Success)
                {
                    Console.WriteLine(resp.Status.Msg);
                }
                var paths = resp.Get(0)?.AsPaths();

                Console.WriteLine($"Count ={paths.Count()}");
                return true;
            }
        ),
        OnEnd = () => Console.WriteLine("End"),
    },
    requestConfig
);

Output
Start
Count =  1390
End

Full Example

C#
using System.Security.Cryptography.X509Certificates;
using Microsoft.Extensions.Logging;
using UltipaService;
using UltipaSharp;
using UltipaSharp.api;
using UltipaSharp.configuration;
using UltipaSharp.connection;
using UltipaSharp.exceptions;
using UltipaSharp.structs;
using UltipaSharp.utils;
using Property = UltipaSharp.structs.Property;

class Program
{
    static async Task Main(string[] args)
    {
        // Connection configurations
        // URI example: Hosts=new[]{"mqj4zouys.us-east-1.cloud.ultipa.com:60010"}
        var myconfig = new UltipaConfig()
        {
            Hosts = new[] { "192.168.1.85:60061", "192.168.1.86:60061", "192.168.1.87:60061" },
            Username = "<username>",
            Password = "<username>",
        };

        // Establishes connection to the database
        var ultipa = new Ultipa(myconfig);
        var isSuccess = ultipa.Test();
        Console.WriteLine(isSuccess);

        // Request configurations
        RequestConfig requestConfig = new RequestConfig() { Graph = "miniCircle", UseMaster = true };

        // Retrieves 10 nodes and prints the _id and name property value of the first returned one
        var res = await ultipa.Gql("MATCH (n:movie) RETURN n LIMIT 10", requestConfig);
        var nodeList = res?.Get(0).AsNodes();
        if (nodeList[0].Values.TryGetValue("name", out object? value))
        {
            Console.WriteLine(value);
        }
        Console.WriteLine(nodeList[0].Id);
    }
}