add schemaless example

docs-cn/06-insert-data/_py_line.mdx

+```py
+{{#include docs-examples/python/line_protocol_example.py}}
+```

docs-cn/06-insert-data/_py_opts_json.mdx

+```py
+{{#include docs-examples/python/json_protocol_example.py}}
+```

docs-cn/06-insert-data/_py_opts_telnet.mdx

+```py
+{{#include docs-examples/python/telnet_line_protocol_example.py}}
+```

docs-cn/14-reference/03-connector/python.mdx

@@ -281,75 +281,3 @@ k1 = conn.query("select info->'k1' as k1 from s1").fetch_all_into_dict()
 - _connect_ 方法
 
   用于生成 taos.TaosConnection 的实例。
-
-## <a class="anchor" id="restful"></a>RESTful Connector
-
-为支持各种不同类型平台的开发，TDengine 提供符合 REST 设计标准的 API，即 RESTful API。为最大程度降低学习成本，不同于其他数据库 RESTful API 的设计方法，TDengine 直接通过 HTTP POST 请求 BODY 中包含的 SQL 语句来操作数据库，仅需要一个 URL。RESTful 连接器的使用参见[视频教程](https://www.taosdata.com/blog/2020/11/11/1965.html)。
-
-注意：与原生连接器的一个区别是，RESTful 接口是无状态的，因此 `USE db_name` 指令没有效果，所有对表名、超级表名的引用都需要指定数据库名前缀。（从 2.2.0.0 版本开始，支持在 RESTful url 中指定 db_name，这时如果 SQL 语句中没有指定数据库名前缀的话，会使用 url 中指定的这个 db_name。从 2.4.0.0 版本开始，RESTful 默认有 taosAdapter 提供，要求必须在 url 中指定 db_name。）
-
-### 安装
-
-RESTful 接口不依赖于任何 TDengine 的库，因此客户端不需要安装任何 TDengine 的库，只要客户端的开发语言支持 HTTP 协议即可。
-
-### 验证
-
-在已经安装 TDengine 服务器端的情况下，可以按照如下方式进行验证。
-
-下面以 Ubuntu 环境中使用 curl 工具（确认已经安装）来验证 RESTful 接口的正常。
-
-下面示例是列出所有的数据库，请把 h1.taosdata.com 和 6041（缺省值）替换为实际运行的 TDengine 服务 fqdn 和端口号：
-
-```html
-curl -H 'Authorization: Basic cm9vdDp0YW9zZGF0YQ==' -d 'show databases;'
-h1.taosdata.com:6041/rest/sql
-```
-
-返回值结果如下表示验证通过：
-
-```json
-{
-  "status": "succ",
-  "head": [
-    "name",
-    "created_time",
-    "ntables",
-    "vgroups",
-    "replica",
-    "quorum",
-    "days",
-    "keep1,keep2,keep(D)",
-    "cache(MB)",
-    "blocks",
-    "minrows",
-    "maxrows",
-    "wallevel",
-    "fsync",
-    "comp",
-    "precision",
-    "status"
-  ],
-  "data": [
-    [
-      "log",
-      "2020-09-02 17:23:00.039",
-      4,
-      1,
-      1,
-      1,
-      10,
-      "30,30,30",
-      1,
-      3,
-      100,
-      4096,
-      1,
-      3000,
-      2,
-      "us",
-      "ready"
-    ]
-  ],
-  "rows": 1
-}
-```

docs-examples/c/.gitignore

+*
+!*.c
+!.gitignore

docs-examples/c/json_protocol_example.c

+// compile with
+// gcc connect_example.c -o connect_example -I /usr/local/taos/include -L /usr/local/taos/driver -ltaos
+#include <stdio.h>
+#include "taos.h"
+#include "taoserror.h"
+
+int main() {
+  // if don't want to connect to a default db, set it to NULL.
+  const char *db = "test";
+  TAOS       *taos = taos_connect("localhost", "root", "taosdata", db, 6030);
+  printf("Connected\n");
+  char *message[] = {
+"[                                       \
+  {                                      \
+     \"metric\":\"cpu_load_1\",          \
+     \"timestamp\": 1626006833,    \
+     \"value\": 55.5,                    \
+     \"tags\":                           \
+         {                               \
+             \"host\": \"ubuntu\",       \
+             \"interface\": \"eth1\",    \
+             \"Id\": \"tb1\"             \
+         }                               \
+  },                                     \
+  {                                      \
+     \"metric\":\"cpu_load_2\",          \
+     \"timestamp\": 1626006833,    \
+     \"value\": 55.5,                    \
+     \"tags\":                           \
+         {                               \
+             \"host\": \"ubuntu\",       \
+             \"interface\": \"eth2\",    \
+             \"Id\": \"tb2\"             \
+         }                               \
+  }                                      \
+ ]",
+ "[                                       \
+  {                                      \
+     \"metric\":\"cpu_load_1\",          \
+     \"timestamp\": 1626006834,    \
+     \"value\": 56.5,                    \
+     \"tags\":                           \
+         {                               \
+             \"host\": \"ubuntu\",       \
+             \"interface\": \"eth1\",    \
+             \"Id\": \"tb1\"             \
+         }                               \
+  },                                     \
+  {                                      \
+     \"metric\":\"cpu_load_2\",          \
+     \"timestamp\": 1626006834,    \
+     \"value\": 56.5,                    \
+     \"tags\":                           \
+         {                               \
+             \"host\": \"ubuntu\",       \
+             \"interface\": \"eth2\",    \
+             \"Id\": \"tb2\"             \
+         }                               \
+  }                                      \
+ ]"
+ };
+void*  code = taos_schemaless_insert(taos, message, 1, 3, NULL);
+if (code) {
+  printf("payload_1 code: %d, %s.\n", code, tstrerror(code));
+}
+  taos_close(taos);
+}

docs-examples/java/src/main/java/com/taos/example/JSONProtocolExample.java

 package com.taos.example;
 
 public class JSONProtocolExample {
+
 }

docs-examples/java/src/main/java/com/taos/example/LineProtocolExample.java

 package com.taos.example;
 
+import com.taosdata.jdbc.SchemalessWriter;
+import com.taosdata.jdbc.enums.SchemalessProtocolType;
+import com.taosdata.jdbc.enums.SchemalessTimestampType;
+
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.SQLException;
+import java.sql.Statement;
+
 public class LineProtocolExample {
+    // format: measurement,tag_set field_set timestamp
+    private static String[] lines = {
+            "meters,location=Beijing.Chaoyang,groupid=2 current=10.3,voltage=219,phase=0.31 1648432611249300", // micro seconds
+            "meters,location=Beijing.Chaoyang,groupid=2 current=12.6,voltage=218,phase=0.33 1648432611249800",
+            "meters,location=Beijing.Chaoyang,groupid=2 current=12.3,voltage=221,phase=0.31 1648432611250300",
+            "meters,location=Beijing.Chaoyang,groupid=3 current=10.3,voltage=218,phase=0.25 1648432611249200",
+            "meters,location=Beijing.Haidian,groupid=2 current=11.8,voltage=221,phase=0.28 1648432611249000",
+            "meters,location=Beijing.Haidian,groupid=2 current=13.4,voltage=223,phase=0.29 1648432611249500",
+            "meters,location=Beijing.Haidian,groupid=3 current=10.8,voltage=223,phase=0.29 1648432611249300",
+            "meters,location=Beijing.Haidian,groupid=3 current=11.3,voltage=221,phase=0.35 1648432611249800",
+    };
+
+    private static Connection getConnection() throws SQLException {
+        String jdbcUrl = "jdbc:TAOS://localhost:6030?user=root&password=taosdata";
+        return DriverManager.getConnection(jdbcUrl);
+    }
+
+    private static void createDatabase(Connection conn) throws SQLException {
+        try (Statement stmt = conn.createStatement()) {
+            // the default precision is ms (microsecond), but we use us(microsecond) here.
+            stmt.execute("create database test precision 'us'");
+            stmt.execute("use test");
+        }
+    }
+
+    public static void main(String[] args) throws SQLException {
+        try (Connection conn = getConnection()) {
+            createDatabase(conn);
+            SchemalessWriter writer = new SchemalessWriter(conn);
+            writer.write(lines, SchemalessProtocolType.LINE, SchemalessTimestampType.MICRO_SECONDS);
+        }
+    }
 }
+

docs-examples/java/src/main/java/com/taos/example/TelnetLineProtocolExample.java

 package com.taos.example;
 
+import com.taosdata.jdbc.SchemalessWriter;
+import com.taosdata.jdbc.enums.SchemalessProtocolType;
+import com.taosdata.jdbc.enums.SchemalessTimestampType;
+
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.SQLException;
+import java.sql.Statement;
+
 public class TelnetLineProtocolExample {
+    // format: <metric> <timestamp> <value> <tagk_1>=<tagv_1>[ <tagk_n>=<tagv_n>]
+    private static String[] lines = {"meters.current 1648432611249 10.3 location=Beijing.Chaoyang groupid=2",
+            "meters.current 1648432611250 12.6 location=Beijing.Chaoyang groupid=2",
+            "meters.current 1648432611249 10.8 location=Beijing.Haidian groupid=3",
+            "meters.current 1648432611250 11.3 location=Beijing.Haidian groupid=3",
+            "meters.voltage 1648432611249 219 location=Beijing.Chaoyang groupid=2",
+            "meters.voltage 1648432611250 218 location=Beijing.Chaoyang groupid=2",
+            "meters.voltage 1648432611249 221 location=Beijing.Haidian groupid=3",
+            "meters.voltage 1648432611250 217 location=Beijing.Haidian groupid=3",
+    };
+
+    private static Connection getConnection() throws SQLException {
+        String jdbcUrl = "jdbc:TAOS://localhost:6030?user=root&password=taosdata";
+        return DriverManager.getConnection(jdbcUrl);
+    }
+
+    private static void createDatabase(Connection conn) throws SQLException {
+        try (Statement stmt = conn.createStatement()) {
+            // the default precision is ms (microsecond), but we use us(microsecond) here.
+            stmt.execute("create database test precision 'us'");
+            stmt.execute("use test");
+        }
+    }
+
+    public static void main(String[] args) throws SQLException {
+        try (Connection conn = getConnection()) {
+            createDatabase(conn);
+            SchemalessWriter writer = new SchemalessWriter(conn);
+            writer.write(lines, SchemalessProtocolType.TELNET, SchemalessTimestampType.NOT_CONFIGURED);
+        }
+    }
+
 }

docs-examples/python/json_protocol_example.py

+import json
+
+import taos
+from taos import SmlProtocol, SmlPrecision
+
+lines = [[{"metric": "meters.current", "timestamp": 1648432611249, "value": 10.3, "tags": {"location": "Beijing.Chaoyang", "groupid": 2}},
+          {"metric": "meters.voltage", "timestamp": 1648432611249, "value": 219, "tags": {"location": "Beijing.Haidian", "groupid": 1}}],
+         [{"metric": "meters.current", "timestamp": 1648432611250, "value": 12.6, "tags": {"location": "Beijing.Chaoyang", "groupid": 2}},
+          {"metric": "meters.voltage", "timestamp": 1648432611250, "value": 221, "tags": {"location": "Beijing.Haidian", "groupid": 1}}]
+         ]
+
+# create connection use firstEP in taos.cfg.
+conn = taos.connect()
+
+
+def create_database():
+    conn.execute("create database test")
+    conn.execute("use test")
+
+
+def insert_lines():
+    global lines
+    lines = [json.dumps(line) for line in lines]
+    print(lines)
+    affected_rows = conn.schemaless_insert(lines, SmlProtocol.JSON_PROTOCOL, SmlPrecision.NOT_CONFIGURED)
+    print(affected_rows)  # 这里有 bug, 4 条数据只写入 2 条。
+
+
+if __name__ == '__main__':
+    create_database()
+    insert_lines()

docs-examples/python/line_protocol_example.py

+import taos
+from taos import SmlProtocol, SmlPrecision
+
+lines = ["meters,location=Beijing.Chaoyang,groupid=2 current=10.3,voltage=219,phase=0.31 1648432611249300",
+         "meters,location=Beijing.Chaoyang,groupid=2 current=12.6,voltage=218,phase=0.33 1648432611249800",
+         "meters,location=Beijing.Chaoyang,groupid=2 current=12.3,voltage=221,phase=0.31 1648432611250300",
+         "meters,location=Beijing.Chaoyang,groupid=3 current=10.3,voltage=218,phase=0.25 1648432611249200",
+         "meters,location=Beijing.Haidian,groupid=2 current=11.8,voltage=221,phase=0.28 1648432611249000",
+         "meters,location=Beijing.Haidian,groupid=2 current=13.4,voltage=223,phase=0.29 1648432611249500",
+         "meters,location=Beijing.Haidian,groupid=3 current=10.8,voltage=223,phase=0.29 1648432611249300",
+         "meters,location=Beijing.Haidian,groupid=3 current=11.3,voltage=221,phase=0.35 1648432611249800",
+         ]
+
+# create connection use firstEP in taos.cfg.
+conn = taos.connect()
+
+
+def create_database():
+    # the default precision is ms (microsecond), but we use us(microsecond) here.
+    conn.execute("create database test precision 'us'")
+    conn.execute("use test")
+
+
+def insert_lines():
+    affected_rows = conn.schemaless_insert(lines, SmlProtocol.LINE_PROTOCOL, SmlPrecision.MICRO_SECONDS)
+    print(affected_rows)  # 8
+
+
+if __name__ == '__main__':
+    create_database()
+    insert_lines()

docs-examples/python/telnet_line_protocol_example.py

+import taos
+from taos import SmlProtocol, SmlPrecision
+
+# format: <metric> <timestamp> <value> <tagk_1>=<tagv_1>[ <tagk_n>=<tagv_n>]
+lines = ["meters.current 1648432611249 10.3 location=Beijing.Chaoyang groupid=2",
+         "meters.current 1648432611250 12.6 location=Beijing.Chaoyang groupid=2",
+         "meters.current 1648432611249 10.8 location=Beijing.Haidian groupid=3",
+         "meters.current 1648432611250 11.3 location=Beijing.Haidian groupid=3",
+         "meters.voltage 1648432611249 219 location=Beijing.Chaoyang groupid=2",
+         "meters.voltage 1648432611250 218 location=Beijing.Chaoyang groupid=2",
+         "meters.voltage 1648432611249 221 location=Beijing.Haidian groupid=3",
+         "meters.voltage 1648432611250 217 location=Beijing.Haidian groupid=3",
+         ]
+
+# create connection use firstEP in taos.cfg.
+conn = taos.connect()
+
+
+def create_database():
+    conn.execute("create database test")
+    conn.execute("use test")
+
+
+def insert_lines():
+    affected_rows = conn.schemaless_insert(lines, SmlProtocol.TELNET_PROTOCOL, SmlPrecision.NOT_CONFIGURED)
+    print(affected_rows)  # 8
+
+
+if __name__ == '__main__':
+    create_database()
+    insert_lines()