C# Connector
TDengine.Connector
is a C# language connector provided by TDengine that allows C# developers to develop C# applications that access TDengine cluster data.
The TDengine.Connector
connector supports connect to TDengine instances via the TDengine client driver (taosc), providing data writing, querying, subscription, schemaless writing, bind interface, etc.The TDengine.Connector
also supports WebSocket from v3.0.1 and developers can build connection through DSN, which supports data writing, querying, and parameter binding, etc.
This article describes how to install TDengine.Connector
in a Linux or Windows environment and connect to TDengine clusters via TDengine.Connector
to perform basic operations such as data writing and querying.
Note: TDengine Connector 3.x is not compatible with TDengine 2.x. In an environment with TDengine 2.x, you must use TDengine.Connector 1.x for the C# connector.
The source code of TDengine.Connector
is hosted on GitHub.
Supported platforms
The supported platforms are the same as those supported by the TDengine client driver.
note
Please note TDengine does not support 32bit Windows any more.
Version support
Please refer to version support list
Supported features
- Native Connection
- WebSocket Connection
- Connection Management
- General Query
- Continuous Query
- Parameter Binding
- Subscription
- Schemaless
- Connection Management
- General Query
- Continuous Query
- Parameter Binding
Installation Steps
Pre-installation preparation
- Install the .NET SDK
- Nuget Client (optional installation)
- Install TDengine client driver, please refer to Install client driver for details
Install TDengine.Connector
- Native Connection
- WebSocket Connection
You can reference the TDengine.Connector
published in Nuget to the current project via the dotnet
CLI under the path of the existing .NET project.
dotnet add package TDengine.Connector
You may also modify the current.NET project file. You can include the following 'ItemGroup' in your project file (.csproj).
<ItemGroup>
<PackageReference Include="TDengine.Connector" Version="3.0.*" />
</ItemGroup>
In this scenario, modifying your project file is required in order to copy the WebSocket dependency dynamic library from the nuget package into your project.
<ItemGroup>
<PackageReference Include="TDengine.Connector" Version="3.0.*" GeneratePathProperty="true" />
</ItemGroup>
<Target Name="copyDLLDependency" BeforeTargets="BeforeBuild">
<ItemGroup>
<DepDLLFiles Include="$(PkgTDengine_Connector)\runtimes\**\*.*" />
</ItemGroup>
<Copy SourceFiles="@(DepDLLFiles)" DestinationFolder="$(OutDir)" />
</Target>
Notice: TDengine.Connector
only version>= 3.0.2 includes the dynamic library for WebSocket.
Establish a Connection
- Native Connection
- WebSocket Connection
using TDengineDriver;
namespace TDengineExample
{
internal class EstablishConnection
{
static void Main(String[] args)
{
string host = "localhost";
short port = 6030;
string username = "root";
string password = "taosdata";
string dbname = "";
var conn = TDengine.Connect(host, username, password, dbname, port);
if (conn == IntPtr.Zero)
{
Console.WriteLine("Connect to TDengine failed");
}
else
{
Console.WriteLine("Connect to TDengine success");
}
TDengine.Close(conn);
TDengine.Cleanup();
}
}
}
The structure of the DSN description string is as follows:
[<protocol>]://[[<username>:<password>@]<host>:<port>][/<database>][?<p1>=<v1>[&<p2>=<v2>]]
|------------|---|-----------|-----------|------|------|------------|-----------------------|
| protocol | | username | password | host | port | database | params |
The parameters are described as follows:
- protocol: Specify which connection method to use (support http/ws). For example,
ws://localhost:6041
uses Websocket to establish connections. - username/password: Username and password used to create connections.
- host/port: Specifies the server and port to establish a connection. Websocket connections default to
localhost:6041
. - database: Specify the default database to connect to. It's optional.
- params: Optional parameters.
A sample DSN description string is as follows:
ws://localhost:6041/test
using System;
using TDengineWS.Impl;
namespace Examples
{
public class WSConnExample
{
static int Main(string[] args)
{
string DSN = "ws://root:taosdata@127.0.0.1:6041/test";
IntPtr wsConn = LibTaosWS.WSConnectWithDSN(DSN);
if (wsConn == IntPtr.Zero)
{
Console.WriteLine("get WS connection failed");
return -1;
}
else
{
Console.WriteLine("Establish connect success.");
// close connection.
LibTaosWS.WSClose(wsConn);
}
return 0;
}
}
}
Usage examples
Write data
SQL Write
- Native Connection
- WebSocket Connection
using TDengineDriver;
namespace TDengineExample
{
internal class SQLInsertExample
{
static void Main()
{
IntPtr conn = GetConnection();
try
{
IntPtr res = TDengine.Query(conn, "CREATE DATABASE power WAL_RETENTION_PERIOD 3600");
CheckRes(conn, res, "failed to create database");
res = TDengine.Query(conn, "USE power");
CheckRes(conn, res, "failed to change database");
res = TDengine.Query(conn, "CREATE STABLE power.meters (ts TIMESTAMP, current FLOAT, voltage INT, phase FLOAT) TAGS (location BINARY(64), groupId INT)");
CheckRes(conn, res, "failed to create stable");
var sql = "INSERT INTO d1001 USING meters TAGS('California.SanFrancisco', 2) VALUES ('2018-10-03 14:38:05.000', 10.30000, 219, 0.31000) ('2018-10-03 14:38:15.000', 12.60000, 218, 0.33000) ('2018-10-03 14:38:16.800', 12.30000, 221, 0.31000) " +
"d1002 USING power.meters TAGS('California.SanFrancisco', 3) VALUES('2018-10-03 14:38:16.650', 10.30000, 218, 0.25000) " +
"d1003 USING power.meters TAGS('California.LosAngeles', 2) VALUES('2018-10-03 14:38:05.500', 11.80000, 221, 0.28000)('2018-10-03 14:38:16.600', 13.40000, 223, 0.29000) " +
"d1004 USING power.meters TAGS('California.LosAngeles', 3) VALUES('2018-10-03 14:38:05.000', 10.80000, 223, 0.29000)('2018-10-03 14:38:06.500', 11.50000, 221, 0.35000)";
res = TDengine.Query(conn, sql);
CheckRes(conn, res, "failed to insert data");
int affectedRows = TDengine.AffectRows(res);
Console.WriteLine("affectedRows " + affectedRows);
TDengine.FreeResult(res);
}
finally
{
TDengine.Close(conn);
}
}
static IntPtr GetConnection()
{
string host = "localhost";
short port = 6030;
string username = "root";
string password = "taosdata";
string dbname = "";
var conn = TDengine.Connect(host, username, password, dbname, port);
if (conn == IntPtr.Zero)
{
throw new Exception("Connect to TDengine failed");
}
else
{
Console.WriteLine("Connect to TDengine success");
}
return conn;
}
static void CheckRes(IntPtr conn, IntPtr res, String errorMsg)
{
if (TDengine.ErrorNo(res) != 0)
{
throw new Exception($"{errorMsg} since: {TDengine.Error(res)}");
}
}
}
}
// output:
// Connect to TDengine success
// affectedRows 8
using System;
using TDengineWS.Impl;
namespace Examples
{
public class WSInsertExample
{
static int Main(string[] args)
{
string DSN = "ws://root:taosdata@127.0.0.1:6041/test";
IntPtr wsConn = LibTaosWS.WSConnectWithDSN(DSN);
// Assert if connection is validate
if (wsConn == IntPtr.Zero)
{
Console.WriteLine("get WS connection failed");
return -1;
}
else
{
Console.WriteLine("Establish connect success.");
}
string createTable = "CREATE STABLE test.meters (ts timestamp, current float, voltage int, phase float) TAGS (location binary(64), groupId int);";
string insert = "INSERT INTO test.d1001 USING test.meters TAGS('California.SanFrancisco', 2) VALUES ('2018-10-03 14:38:05.000', 10.30000, 219, 0.31000) ('2018-10-03 14:38:15.000', 12.60000, 218, 0.33000) ('2018-10-03 14:38:16.800', 12.30000, 221, 0.31000)" +
"test.d1002 USING test.meters TAGS('California.SanFrancisco', 3) VALUES('2018-10-03 14:38:16.650', 10.30000, 218, 0.25000)" +
"test.d1003 USING test.meters TAGS('California.LosAngeles', 2) VALUES('2018-10-03 14:38:05.500', 11.80000, 221, 0.28000)('2018-10-03 14:38:16.600', 13.40000, 223, 0.29000) " +
"test.d1004 USING test.meters TAGS('California.LosAngeles', 3) VALUES('2018-10-03 14:38:05.000', 10.80000, 223, 0.29000)('2018-10-03 14:38:06.500', 11.50000, 221, 0.35000)";
IntPtr wsRes = LibTaosWS.WSQuery(wsConn, createTable);
ValidInsert("create table", wsRes);
LibTaosWS.WSFreeResult(wsRes);
wsRes = LibTaosWS.WSQuery(wsConn, insert);
ValidInsert("insert data", wsRes);
LibTaosWS.WSFreeResult(wsRes);
// close connection.
LibTaosWS.WSClose(wsConn);
return 0;
}
static void ValidInsert(string desc, IntPtr wsRes)
{
int code = LibTaosWS.WSErrorNo(wsRes);
if (code != 0)
{
Console.WriteLine($"execute SQL failed: reason: {LibTaosWS.WSErrorStr(wsRes)}, code:{code}");
}
else
{
Console.WriteLine("{0} success affect {2} rows, cost {1} nanoseconds", desc, LibTaosWS.WSTakeTiming(wsRes), LibTaosWS.WSAffectRows(wsRes));
}
}
}
}
// Establish connect success.
// create table success affect 0 rows, cost 3717542 nanoseconds
// insert data success affect 8 rows, cost 2613637 nanoseconds
InfluxDB line protocol write
using TDengineDriver;
namespace TDengineExample
{
internal class InfluxDBLineExample
{
static void Main()
{
IntPtr conn = GetConnection();
PrepareDatabase(conn);
string[] lines = {
"meters,location=California.LosAngeles,groupid=2 current=11.8,voltage=221,phase=0.28 1648432611249",
"meters,location=California.LosAngeles,groupid=2 current=13.4,voltage=223,phase=0.29 1648432611250",
"meters,location=California.LosAngeles,groupid=3 current=10.8,voltage=223,phase=0.29 1648432611249",
"meters,location=California.LosAngeles,groupid=3 current=11.3,voltage=221,phase=0.35 1648432611250"
};
IntPtr res = TDengine.SchemalessInsert(conn, lines, lines.Length, (int)TDengineSchemalessProtocol.TSDB_SML_LINE_PROTOCOL, (int)TDengineSchemalessPrecision.TSDB_SML_TIMESTAMP_MILLI_SECONDS);
if (TDengine.ErrorNo(res) != 0)
{
throw new Exception("SchemalessInsert failed since " + TDengine.Error(res));
}
else
{
int affectedRows = TDengine.AffectRows(res);
Console.WriteLine($"SchemalessInsert success, affected {affectedRows} rows");
}
TDengine.FreeResult(res);
}
static IntPtr GetConnection()
{
string host = "localhost";
short port = 6030;
string username = "root";
string password = "taosdata";
string dbname = "";
var conn = TDengine.Connect(host, username, password, dbname, port);
if (conn == IntPtr.Zero)
{
throw new Exception("Connect to TDengine failed");
}
else
{
Console.WriteLine("Connect to TDengine success");
}
return conn;
}
static void PrepareDatabase(IntPtr conn)
{
IntPtr res = TDengine.Query(conn, "CREATE DATABASE test WAL_RETENTION_PERIOD 3600");
if (TDengine.ErrorNo(res) != 0)
{
throw new Exception("failed to create database, reason: " + TDengine.Error(res));
}
res = TDengine.Query(conn, "USE test");
if (TDengine.ErrorNo(res) != 0)
{
throw new Exception("failed to change database, reason: " + TDengine.Error(res));
}
}
}
}
OpenTSDB Telnet line protocol write
using TDengineDriver;
namespace TDengineExample
{
internal class OptsTelnetExample
{
static void Main()
{
IntPtr conn = GetConnection();
try
{
PrepareDatabase(conn);
string[] lines = {
"meters.current 1648432611249 10.3 location=California.SanFrancisco groupid=2",
"meters.current 1648432611250 12.6 location=California.SanFrancisco groupid=2",
"meters.current 1648432611249 10.8 location=California.LosAngeles groupid=3",
"meters.current 1648432611250 11.3 location=California.LosAngeles groupid=3",
"meters.voltage 1648432611249 219 location=California.SanFrancisco groupid=2",
"meters.voltage 1648432611250 218 location=California.SanFrancisco groupid=2",
"meters.voltage 1648432611249 221 location=California.LosAngeles groupid=3",
"meters.voltage 1648432611250 217 location=California.LosAngeles groupid=3",
};
IntPtr res = TDengine.SchemalessInsert(conn, lines, lines.Length, (int)TDengineSchemalessProtocol.TSDB_SML_TELNET_PROTOCOL, (int)TDengineSchemalessPrecision.TSDB_SML_TIMESTAMP_NOT_CONFIGURED);
if (TDengine.ErrorNo(res) != 0)
{
throw new Exception("SchemalessInsert failed since " + TDengine.Error(res));
}
else
{
int affectedRows = TDengine.AffectRows(res);
Console.WriteLine($"SchemalessInsert success, affected {affectedRows} rows");
}
TDengine.FreeResult(res);
}
catch
{
TDengine.Close(conn);
}
}
static IntPtr GetConnection()
{
string host = "localhost";
short port = 6030;
string username = "root";
string password = "taosdata";
string dbname = "";
var conn = TDengine.Connect(host, username, password, dbname, port);
if (conn == IntPtr.Zero)
{
throw new Exception("Connect to TDengine failed");
}
else
{
Console.WriteLine("Connect to TDengine success");
}
return conn;
}
static void PrepareDatabase(IntPtr conn)
{
IntPtr res = TDengine.Query(conn, "CREATE DATABASE test WAL_RETENTION_PERIOD 3600");
if (TDengine.ErrorNo(res) != 0)
{
throw new Exception("failed to create database, reason: " + TDengine.Error(res));
}
res = TDengine.Query(conn, "USE test");
if (TDengine.ErrorNo(res) != 0)
{
throw new Exception("failed to change database, reason: " + TDengine.Error(res));
}
}
}
}
OpenTSDB JSON line protocol write
using TDengineDriver;
namespace TDengineExample
{
internal class OptsJsonExample
{
static void Main()
{
IntPtr conn = GetConnection();
try
{
PrepareDatabase(conn);
string[] lines = { "[{\"metric\": \"meters.current\", \"timestamp\": 1648432611249, \"value\": 10.3, \"tags\": {\"location\": \"California.SanFrancisco\", \"groupid\": 2}}," +
" {\"metric\": \"meters.voltage\", \"timestamp\": 1648432611249, \"value\": 219, \"tags\": {\"location\": \"California.LosAngeles\", \"groupid\": 1}}, " +
"{\"metric\": \"meters.current\", \"timestamp\": 1648432611250, \"value\": 12.6, \"tags\": {\"location\": \"California.SanFrancisco\", \"groupid\": 2}}," +
" {\"metric\": \"meters.voltage\", \"timestamp\": 1648432611250, \"value\": 221, \"tags\": {\"location\": \"California.LosAngeles\", \"groupid\": 1}}]"
};
IntPtr res = TDengine.SchemalessInsert(conn, lines, 1, (int)TDengineSchemalessProtocol.TSDB_SML_JSON_PROTOCOL, (int)TDengineSchemalessPrecision.TSDB_SML_TIMESTAMP_NOT_CONFIGURED);
if (TDengine.ErrorNo(res) != 0)
{
throw new Exception("SchemalessInsert failed since " + TDengine.Error(res));
}
else
{
int affectedRows = TDengine.AffectRows(res);
Console.WriteLine($"SchemalessInsert success, affected {affectedRows} rows");
}
TDengine.FreeResult(res);
}
finally
{
TDengine.Close(conn);
}
}
static IntPtr GetConnection()
{
string host = "localhost";
short port = 6030;
string username = "root";
string password = "taosdata";
string dbname = "";
var conn = TDengine.Connect(host, username, password, dbname, port);
if (conn == IntPtr.Zero)
{
throw new Exception("Connect to TDengine failed");
}
else
{
Console.WriteLine("Connect to TDengine success");
}
return conn;
}
static void PrepareDatabase(IntPtr conn)
{
IntPtr res = TDengine.Query(conn, "CREATE DATABASE test WAL_RETENTION_PERIOD 3600");
if (TDengine.ErrorNo(res) != 0)
{
throw new Exception("failed to create database, reason: " + TDengine.Error(res));
}
res = TDengine.Query(conn, "USE test");
if (TDengine.ErrorNo(res) != 0)
{
throw new Exception("failed to change database, reason: " + TDengine.Error(res));
}
}
}
}
Parameter Binding
- Native Connection
- WebSocket Connection
using TDengineDriver;
namespace TDengineExample
{
internal class StmtInsertExample
{
private static IntPtr conn;
private static IntPtr stmt;
static void Main()
{
conn = GetConnection();
try
{
PrepareSTable();
// 1. init and prepare
stmt = TDengine.StmtInit(conn);
if (stmt == IntPtr.Zero)
{
throw new Exception("failed to init stmt.");
}
int res = TDengine.StmtPrepare(stmt, "INSERT INTO ? USING meters TAGS(?, ?) VALUES(?, ?, ?, ?)");
CheckStmtRes(res, "failed to prepare stmt");
// 2. bind table name and tags
TAOS_MULTI_BIND[] tags = new TAOS_MULTI_BIND[2] { TaosMultiBind.MultiBindBinary(new string[] { "California.SanFrancisco" }), TaosMultiBind.MultiBindInt(new int?[] { 2 }) };
res = TDengine.StmtSetTbnameTags(stmt, "d1001", tags);
CheckStmtRes(res, "failed to bind table name and tags");
// 3. bind values
TAOS_MULTI_BIND[] values = new TAOS_MULTI_BIND[4] {
TaosMultiBind.MultiBindTimestamp(new long[2] { 1648432611249, 1648432611749}),
TaosMultiBind.MultiBindFloat(new float?[2] { 10.3f, 12.6f}),
TaosMultiBind.MultiBindInt(new int?[2] { 219, 218}),
TaosMultiBind.MultiBindFloat(new float?[2]{ 0.31f, 0.33f})
};
res = TDengine.StmtBindParamBatch(stmt, values);
CheckStmtRes(res, "failed to bind params");
// 4. add batch
res = TDengine.StmtAddBatch(stmt);
CheckStmtRes(res, "failed to add batch");
// 5. execute
res = TDengine.StmtExecute(stmt);
CheckStmtRes(res, "failed to execute");
// 6. free
TaosMultiBind.FreeTaosBind(tags);
TaosMultiBind.FreeTaosBind(values);
}
finally
{
TDengine.Close(conn);
}
}
static IntPtr GetConnection()
{
string host = "localhost";
short port = 6030;
string username = "root";
string password = "taosdata";
string dbname = "";
var conn = TDengine.Connect(host, username, password, dbname, port);
if (conn == IntPtr.Zero)
{
throw new Exception("Connect to TDengine failed");
}
else
{
Console.WriteLine("Connect to TDengine success");
}
return conn;
}
static void PrepareSTable()
{
IntPtr res = TDengine.Query(conn, "CREATE DATABASE power WAL_RETENTION_PERIOD 3600");
CheckResPtr(res, "failed to create database");
res = TDengine.Query(conn, "USE power");
CheckResPtr(res, "failed to change database");
res = TDengine.Query(conn, "CREATE STABLE power.meters (ts TIMESTAMP, current FLOAT, voltage INT, phase FLOAT) TAGS (location BINARY(64), groupId INT)");
CheckResPtr(res, "failed to create stable");
}
static void CheckStmtRes(int res, string errorMsg)
{
if (res != 0)
{
Console.WriteLine(errorMsg + ", " + TDengine.StmtErrorStr(stmt));
int code = TDengine.StmtClose(stmt);
if (code != 0)
{
throw new Exception($"failed to close stmt, {code} reason: {TDengine.StmtErrorStr(stmt)} ");
}
}
}
static void CheckResPtr(IntPtr res, string errorMsg)
{
if (TDengine.ErrorNo(res) != 0)
{
throw new Exception(errorMsg + " since:" + TDengine.Error(res));
}
}
}
}
using System;
using TDengineWS.Impl;
using TDengineDriver;
using System.Runtime.InteropServices;
namespace Examples
{
public class WSStmtExample
{
static int Main(string[] args)
{
const string DSN = "ws://root:taosdata@127.0.0.1:6041/test";
const string table = "meters";
const string database = "test";
const string childTable = "d1005";
string insert = $"insert into ? using {database}.{table} tags(?,?) values(?,?,?,?)";
const int numOfTags = 2;
const int numOfColumns = 4;
// Establish connection
IntPtr wsConn = LibTaosWS.WSConnectWithDSN(DSN);
if (wsConn == IntPtr.Zero)
{
Console.WriteLine($"get WS connection failed");
return -1;
}
else
{
Console.WriteLine("Establish connect success...");
}
// init stmt
IntPtr wsStmt = LibTaosWS.WSStmtInit(wsConn);
if (wsStmt != IntPtr.Zero)
{
int code = LibTaosWS.WSStmtPrepare(wsStmt, insert);
ValidStmtStep(code, wsStmt, "WSStmtPrepare");
TAOS_MULTI_BIND[] wsTags = new TAOS_MULTI_BIND[] { WSMultiBind.WSBindNchar(new string[] { "California.SanDiego" }), WSMultiBind.WSBindInt(new int?[] { 4 }) };
code = LibTaosWS.WSStmtSetTbnameTags(wsStmt, $"{database}.{childTable}", wsTags, numOfTags);
ValidStmtStep(code, wsStmt, "WSStmtSetTbnameTags");
TAOS_MULTI_BIND[] data = new TAOS_MULTI_BIND[4];
data[0] = WSMultiBind.WSBindTimestamp(new long[] { 1538548687000, 1538548688000, 1538548689000, 1538548690000, 1538548691000 });
data[1] = WSMultiBind.WSBindFloat(new float?[] { 10.30F, 10.40F, 10.50F, 10.60F, 10.70F });
data[2] = WSMultiBind.WSBindInt(new int?[] { 223, 221, 222, 220, 219 });
data[3] = WSMultiBind.WSBindFloat(new float?[] { 0.31F, 0.32F, 0.33F, 0.35F, 0.28F });
code = LibTaosWS.WSStmtBindParamBatch(wsStmt, data, numOfColumns);
ValidStmtStep(code, wsStmt, "WSStmtBindParamBatch");
code = LibTaosWS.WSStmtAddBatch(wsStmt);
ValidStmtStep(code, wsStmt, "WSStmtAddBatch");
IntPtr stmtAffectRowPtr = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(Int32)));
code = LibTaosWS.WSStmtExecute(wsStmt, stmtAffectRowPtr);
ValidStmtStep(code, wsStmt, "WSStmtExecute");
Console.WriteLine("WS STMT insert {0} rows...", Marshal.ReadInt32(stmtAffectRowPtr));
Marshal.FreeHGlobal(stmtAffectRowPtr);
LibTaosWS.WSStmtClose(wsStmt);
// Free unmanaged memory
WSMultiBind.WSFreeTaosBind(wsTags);
WSMultiBind.WSFreeTaosBind(data);
//check result with SQL "SELECT * FROM test.d1005;"
}
else
{
Console.WriteLine("Init STMT failed...");
}
// close connection.
LibTaosWS.WSClose(wsConn);
return 0;
}
static void ValidStmtStep(int code, IntPtr wsStmt, string desc)
{
if (code != 0)
{
Console.WriteLine($"{desc} failed,reason: {LibTaosWS.WSErrorStr(wsStmt)}, code: {code}");
}
else
{
Console.WriteLine("{0} success...", desc);
}
}
}
}
// WSStmtPrepare success...
// WSStmtSetTbnameTags success...
// WSStmtBindParamBatch success...
// WSStmtAddBatch success...
// WSStmtExecute success...
// WS STMT insert 5 rows...
Query data
Synchronous Query
- Native Connection
- WebSocket Connection
using TDengineDriver;
using TDengineDriver.Impl;
using System.Runtime.InteropServices;
namespace TDengineExample
{
internal class QueryExample
{
static void Main()
{
IntPtr conn = GetConnection();
try
{
// run query
IntPtr res = TDengine.Query(conn, "SELECT * FROM meters LIMIT 2");
if (TDengine.ErrorNo(res) != 0)
{
throw new Exception("Failed to query since: " + TDengine.Error(res));
}
// get filed count
int fieldCount = TDengine.FieldCount(res);
Console.WriteLine("fieldCount=" + fieldCount);
// print column names
List<TDengineMeta> metas = LibTaos.GetMeta(res);
for (int i = 0; i < metas.Count; i++)
{
Console.Write(metas[i].name + "\t");
}
Console.WriteLine();
// print values
List<Object> resData = LibTaos.GetData(res);
for (int i = 0; i < resData.Count; i++)
{
Console.Write($"|{resData[i].ToString()} \t");
if (((i + 1) % metas.Count == 0))
{
Console.WriteLine("");
}
}
Console.WriteLine();
// Free result after use
TDengine.FreeResult(res);
}
finally
{
TDengine.Close(conn);
}
}
static IntPtr GetConnection()
{
string host = "localhost";
short port = 6030;
string username = "root";
string password = "taosdata";
string dbname = "power";
var conn = TDengine.Connect(host, username, password, dbname, port);
if (conn == IntPtr.Zero)
{
throw new Exception("Connect to TDengine failed");
}
else
{
Console.WriteLine("Connect to TDengine success");
}
return conn;
}
}
}
// output:
// Connect to TDengine success
// fieldCount=6
// ts current voltage phase location groupid
// 1648432611249 10.3 219 0.31 California.SanFrancisco 2
// 1648432611749 12.6 218 0.33 California.SanFrancisco 2
using System;
using TDengineWS.Impl;
using System.Collections.Generic;
using TDengineDriver;
namespace Examples
{
public class WSQueryExample
{
static int Main(string[] args)
{
string DSN = "ws://root:taosdata@127.0.0.1:6041/test";
IntPtr wsConn = LibTaosWS.WSConnectWithDSN(DSN);
if (wsConn == IntPtr.Zero)
{
Console.WriteLine("get WS connection failed");
return -1;
}
else
{
Console.WriteLine("Establish connect success.");
}
string select = "select * from test.meters";
// optional:wsRes = LibTaosWS.WSQuery(wsConn, select);
IntPtr wsRes = LibTaosWS.WSQueryTimeout(wsConn, select, 1);
// Assert if query execute success.
int code = LibTaosWS.WSErrorNo(wsRes);
if (code != 0)
{
Console.WriteLine($"execute SQL failed: reason: {LibTaosWS.WSErrorStr(wsRes)}, code:{code}");
LibTaosWS.WSFreeResult(wsRes);
return -1;
}
// get meta data
List<TDengineMeta> metas = LibTaosWS.WSGetFields(wsRes);
// get retrieved data
List<object> dataSet = LibTaosWS.WSGetData(wsRes);
// do something with result.
foreach (var meta in metas)
{
Console.Write("{0} {1}({2}) \t|\t", meta.name, meta.TypeName(), meta.size);
}
Console.WriteLine("");
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("");
}
// Free result after use.
LibTaosWS.WSFreeResult(wsRes);
// close connection.
LibTaosWS.WSClose(wsConn);
return 0;
}
}
}
// Establish connect success.
// ts TIMESTAMP(8) | current FLOAT(4) | voltage INT(4) | phase FLOAT(4) | location BINARY(64) | groupid INT(4) |
// 1538548685000 | 10.8 | 223 | 0.29 | California.LosAngeles | 3 |
// 1538548686500 | 11.5 | 221 | 0.35 | California.LosAngeles | 3 |
// 1538548685500 | 11.8 | 221 | 0.28 | California.LosAngeles | 2 |
// 1538548696600 | 13.4 | 223 | 0.29 | California.LosAngeles | 2 |
// 1538548685000 | 10.3 | 219 | 0.31 | California.SanFrancisco | 2 |
// 1538548695000 | 12.6 | 218 | 0.33 | California.SanFrancisco | 2 |
// 1538548696800 | 12.3 | 221 | 0.31 | California.SanFrancisco | 2 |
// 1538548696650 | 10.3 | 218 | 0.25 | California.SanFrancisco | 3 |
Asynchronous query
using System;
using System.Collections.Generic;
using TDengineDriver;
using TDengineDriver.Impl;
using System.Runtime.InteropServices;
namespace TDengineExample
{
public class AsyncQueryExample
{
static void Main()
{
IntPtr conn = GetConnection();
try
{
QueryAsyncCallback queryAsyncCallback = new QueryAsyncCallback(QueryCallback);
TDengine.QueryAsync(conn, "select * from meters", queryAsyncCallback, IntPtr.Zero);
Thread.Sleep(2000);
}
finally
{
TDengine.Close(conn);
}
}
static void QueryCallback(IntPtr param, IntPtr taosRes, int code)
{
if (code == 0 && taosRes != IntPtr.Zero)
{
FetchRawBlockAsyncCallback fetchRowAsyncCallback = new FetchRawBlockAsyncCallback(FetchRawBlockCallback);
TDengine.FetchRawBlockAsync(taosRes, fetchRowAsyncCallback, param);
}
else
{
throw new Exception($"async query data failed,code:{code},reason:{TDengine.Error(taosRes)}");
}
}
// Iteratively call this interface until "numOfRows" is no greater than 0.
static void FetchRawBlockCallback(IntPtr param, IntPtr taosRes, int numOfRows)
{
if (numOfRows > 0)
{
Console.WriteLine($"{numOfRows} rows async retrieved");
IntPtr pdata = TDengine.GetRawBlock(taosRes);
List<TDengineMeta> metaList = TDengine.FetchFields(taosRes);
List<object> dataList = LibTaos.ReadRawBlock(pdata, metaList, numOfRows);
for (int i = 0; i < dataList.Count; i++)
{
if (i != 0 && (i + 1) % metaList.Count == 0)
{
Console.WriteLine("{0}\t|", dataList[i]);
}
else
{
Console.Write("{0}\t|", dataList[i]);
}
}
Console.WriteLine("");
TDengine.FetchRawBlockAsync(taosRes, FetchRawBlockCallback, param);
}
else
{
if (numOfRows == 0)
{
Console.WriteLine("async retrieve complete.");
}
else
{
throw new Exception($"FetchRawBlockCallback callback error, error code {numOfRows}");
}
TDengine.FreeResult(taosRes);
}
}
static IntPtr GetConnection()
{
string host = "localhost";
short port = 6030;
string username = "root";
string password = "taosdata";
string dbname = "power";
var conn = TDengine.Connect(host, username, password, dbname, port);
if (conn == IntPtr.Zero)
{
throw new Exception("Connect to TDengine failed");
}
else
{
Console.WriteLine("Connect to TDengine success");
}
return conn;
}
}
}
// //output:
// // Connect to TDengine success
// // 8 rows async retrieved
// // 1538548685500 | 11.8 | 221 | 0.28 | california.losangeles | 2 |
// // 1538548696600 | 13.4 | 223 | 0.29 | california.losangeles | 2 |
// // 1538548685000 | 10.8 | 223 | 0.29 | california.losangeles | 3 |
// // 1538548686500 | 11.5 | 221 | 0.35 | california.losangeles | 3 |
// // 1538548685000 | 10.3 | 219 | 0.31 | california.sanfrancisco | 2 |
// // 1538548695000 | 12.6 | 218 | 0.33 | california.sanfrancisco | 2 |
// // 1538548696800 | 12.3 | 221 | 0.31 | california.sanfrancisco | 2 |
// // 1538548696650 | 10.3 | 218 | 0.25 | california.sanfrancisco | 3 |
// // async retrieve complete.
More sample programs
Sample program | Sample program description |
---|---|
CURD | Table creation, data insertion, and query examples with TDengine.Connector |
JSON Tag | Writing and querying JSON tag data with TDengine Connector |
stmt | Parameter binding with TDengine Connector |
schemaless | Schemaless writes with TDengine Connector |
async query | Asynchronous queries with TDengine Connector |
Subscription | Subscription example with TDengine Connector |
Basic WebSocket Usage | WebSocket basic data in and out with TDengine connector |
WebSocket Parameter Binding | WebSocket parameter binding example |
Important update records
TDengine.Connector | Description |
---|---|
3.0.2 | Support .NET Framework 4.5 and above. Support .Net standard 2.0. Nuget package includes dynamic library for WebSocket. |
3.0.1 | Support WebSocket and Cloud, With function query, insert, and parameter binding |
3.0.0 | Supports TDengine 3.0.0.0. TDengine 2.x is not supported. Added TDengine.Impl.GetData() interface to deserialize query results. |
1.0.7 | Fixed TDengine.Query() memory leak. |
1.0.6 | Fix schemaless bug in 1.0.4 and 1.0.5. |
1.0.5 | Fix Windows sync query Chinese error bug. |
1.0.4 | Add asynchronous query, subscription, and other functions. Fix the binding parameter bug. |
1.0.3 | Add parameter binding, schemaless, JSON tag, etc. |
1.0.2 | Add connection management, synchronous query, error messages, etc. |
Other descriptions
Third-party driver
Taos
is an ADO.NET connector for TDengine, supporting Linux and Windows platforms. Community contributor Maikebing@@maikebing contributes the connector
. Please refer to:
- Interface download:https://github.com/maikebing/Maikebing.EntityFrameworkCore.Taos
Frequently Asked Questions
"Unable to establish connection", "Unable to resolve FQDN"
Usually, it's caused by an incorrect FQDN configuration. Please refer to this section in the FAQ to troubleshoot.
Unhandled exception. System.DllNotFoundException: Unable to load DLL 'taos' or one of its dependencies: The specified module cannot be found.
This is usually because the program did not find the dependent client driver. The solution is to copy
C:\TDengine\driver\taos.dll
to theC:\Windows\System32\
directory on Windows, and create the following soft link on Linuxln -s /usr/local/taos/driver/libtaos.so.x.x .x.x /usr/lib/libtaos.so
will work.