TDengine/docs/examples/csharp/cloud-example/usage/Program.cs

using System;
using TDengineDriver;
using TDengineWS.Impl;
using System.Collections.Generic;

namespace Cloud.Examples
{
    public class UsageExample
    {
        static void Main(string[] args)
        {
            string dsn = Environment.GetEnvironmentVariable("TDENGINE_CLOUD_DSN");
            IntPtr conn = Connect(dsn);
            InsertData(conn);
            SelectData(conn);
            // close connect
            LibTaosWS.WSClose(conn);
        }

        public static IntPtr Connect(string dsn)
        {
            // get connect
            IntPtr conn = LibTaosWS.WSConnectWithDSN(dsn);
            if (conn == IntPtr.Zero)
            {
                throw new Exception($"get connection failed,reason:{LibTaosWS.WSErrorStr(conn)},code:{LibTaosWS.WSErrorNo(conn)}");
            }
            return conn;
        }


        public static void InsertData(IntPtr conn)
        {
            string createTable = "CREATE STABLE if not exists test.meters (ts TIMESTAMP, current FLOAT, voltage INT, phase FLOAT) TAGS (location BINARY(64), groupId INT)";
            string insertData = "INSERT INTO " +
                                "test.d1001 USING test.meters TAGS('California.SanFrancisco', 1) VALUES ('2018-10-03 14:38:05.000', 10.30000, 219, 0.31000)" +
                                "test.d1002 USING test.meters TAGS('California.SanFrancisco', 2) VALUES ('2018-10-03 14:38:16.650', 10.30000, 218, 0.25000)" +
                                "test.d1003 USING test.meters TAGS('California.LosAngeles', 3) VALUES ('2018-10-03 14:38:05.500', 11.80000, 221, 0.28000)" +
                                "test.d1004 USING test.meters TAGS('California.LosAngeles', 4) VALUES ('2018-10-03 14:38:05.000', 10.80000, 223, 0.29000) ";

            // create database under database named 'test'
            IntPtr res = LibTaosWS.WSQuery(conn, createTable);
            ValidQueryExecution(res);
            // Free the query result every time when used up it.
            LibTaosWS.WSFreeResult(res);

            // insert data into the table created in previous step.
            res = LibTaosWS.WSQuery(conn, insertData);
            ValidQueryExecution(res);
            // Free the query result every time when used up it.
            LibTaosWS.WSFreeResult(res);
        }
        public static void SelectData(IntPtr conn)
        {
            string selectTable = "select * from test.meters";
            IntPtr res = LibTaosWS.WSQueryTimeout(conn, selectTable,5000);
            ValidQueryExecution(res);

            // print meta
            List<TDengineMeta> metas = LibTaosWS.WSGetFields(res);
            foreach (var meta in metas)
            {
                Console.Write("{0} {1}({2})\t|", meta.name, meta.TypeName(), meta.size);
            }
            Console.WriteLine("");
            List<object> dataSet = LibTaosWS.WSGetData(res);
            for (int i = 0; i < dataSet.Count;)
            {
                for (int j = 0; j < metas.Count; j++)
                {
                    Console.Write("{0}\t|\t", dataSet[i]);
                    i++;
                }
                Console.WriteLine("");
            }
            Console.WriteLine("");

            // Free the query result every time when used up it.
            LibTaosWS.WSFreeResult(res);
        }

        // Check if LibTaosWS.Query() execute correctly.
        public static void ValidQueryExecution(IntPtr res)
        {
            int code = LibTaosWS.WSErrorNo(res);
            if (code != 0)
            {
                throw new Exception($"execute SQL failed: reason: {LibTaosWS.WSErrorStr(res)}, code:{code}");
            }
        }
    }
}