80 lines
2.4 KiB
C#
80 lines
2.4 KiB
C#
using TDengineDriver;
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using TDengineDriver.Impl;
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using System.Runtime.InteropServices;
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namespace TDengineExample
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{
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internal class QueryExample
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{
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static void Main()
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{
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IntPtr conn = GetConnection();
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try
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{
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// run query
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IntPtr res = TDengine.Query(conn, "SELECT * FROM meters LIMIT 2");
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if (TDengine.ErrorNo(res) != 0)
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{
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throw new Exception("Failed to query since: " + TDengine.Error(res));
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}
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// get filed count
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int fieldCount = TDengine.FieldCount(res);
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Console.WriteLine("fieldCount=" + fieldCount);
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// print column names
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List<TDengineMeta> metas = LibTaos.GetMeta(res);
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for (int i = 0; i < metas.Count; i++)
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{
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Console.Write(metas[i].name + "\t");
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}
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Console.WriteLine();
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// print values
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List<Object> resData = LibTaos.GetData(res);
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for (int i = 0; i < resData.Count; i++)
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{
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Console.Write($"|{resData[i].ToString()} \t");
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if (((i + 1) % metas.Count == 0))
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{
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Console.WriteLine("");
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}
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}
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Console.WriteLine();
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// Free result after use
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TDengine.FreeResult(res);
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}
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finally
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{
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TDengine.Close(conn);
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}
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}
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static IntPtr GetConnection()
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{
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string host = "localhost";
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short port = 6030;
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string username = "root";
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string password = "taosdata";
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string dbname = "power";
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var conn = TDengine.Connect(host, username, password, dbname, port);
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if (conn == IntPtr.Zero)
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{
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throw new Exception("Connect to TDengine failed");
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}
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else
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{
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Console.WriteLine("Connect to TDengine success");
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}
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return conn;
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}
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}
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}
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// output:
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// Connect to TDengine success
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// fieldCount=6
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// ts current voltage phase location groupid
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// 1648432611249 10.3 219 0.31 California.SanFrancisco 2
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// 1648432611749 12.6 218 0.33 California.SanFrancisco 2 |