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T
TDengine
未验证 提交 6d093c34 编写于 作者: B Bo Ding 提交者： GitHub
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c sample codes (#11281) 

* add c examples and subscribe examples files for other languages

* add query example

* c sample code

* c query example
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docs-cn/06-insert-data/_c_line.mdx
浏览文件 @ 6d093c34
```c
{{#include docs-examples/c/line_example.c:main}}
```
\ No newline at end of file
docs-cn/06-insert-data/_c_opts_json.mdx
浏览文件 @ 6d093c34
```c
{{#include docs-examples/c/json_protocol_example.c:main}}
```
\ No newline at end of file
docs-cn/06-insert-data/_c_opts_telnet.mdx
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```c
{{#include docs-examples/c/telnet_line_example.c:main}}
```
\ No newline at end of file
docs-cn/06-insert-data/_c_sql.mdx
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```c
{{#include docs-examples/c/insert_example.c}}
```
\ No newline at end of file
docs-cn/06-insert-data/_c_stmt.mdx
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```c title=一次绑定一行
{{#include docs-examples/c/stmt_example.c}}
```
```c title=一次绑定多行 72:117
{{#include docs-examples/c/multi_bind_example.c}}
```
\ No newline at end of file
docs-cn/07-query-data/_c.mdx
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```c
{{#include docs-examples/c/query_example.c}}
```
\ No newline at end of file
docs-cn/07-query-data/_c_async.mdx
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```c
{{#include docs-examples/c/async_query_example.c}}
```
\ No newline at end of file
docs-cn/08-advance-feature/02-subscribe.mdx
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---
sidebar_position: 2
sidebar_label: 数据订阅
---
......@@ -7,6 +6,13 @@ sidebar_label: 数据订阅
import Tabs from "@theme/Tabs";
import TabItem from "@theme/TabItem";
import Java from "./_sub_java.mdx";
import Python from "./_sub_python.mdx";
import Go from "./_sub_go.mdx";
import Rust from "./_sub_rust.mdx";
import Node from "./_sub_node.mdx";
import CSharp from "./_sub_cs.mdx";
import CDemo from "./_sub_c.mdx";
基于数据天然的时间序列特性，TDengine 的数据写入（insert）与消息系统的数据发布（pub）逻辑上一致，均可视为系统中插入一条带时间戳的新记录。同时，TDengine 在内部严格按照数据时间序列单调递增的方式保存数据。本质上来说，TDengine 中里每一张表均可视为一个标准的消息队列。
......@@ -164,23 +170,9 @@ $ taos
这时，因为电流超过了 10A，您应该可以看到示例程序将它输出到了屏幕上。您可以继续插入一些数据观察示例程序的输出。
## 示例代码
## 示例程序
<Tabs defaultValue="java" groupId="lang">
<TabItem label="Java" value="java"></TabItem>
<TabItem label="Python" value="Python"></TabItem>
<TabItem label="Go" value="go"></TabItem>
<TabItem label="C" value="c"></TabItem>
<TabItem label="Rust" value="rust"></TabItem>
<TabItem label="Node.js" value="nodejs"></TabItem>
<TabItem label="C#" value="csharp"></TabItem>
</Tabs>
## Java 使用数据订阅功能
订阅功能也提供了 Java 开发接口，相关说明请见 [Java Connector](https://www.taosdata.com/cn/documentation/connector/java#subscribe)。需要注意的是，目前 Java 接口没有提供异步订阅模式，但用户程序可以通过创建 `TimerTask` 等方式达到同样的效果。
下面以一个示例程序介绍其具体使用方法。它所完成的功能与前面介绍的 C 语言示例基本相同，也是订阅数据库中所有电流超过 10A 的记录。
下面以一个示例程序介绍其具体使用方法。示例程序的目的是订阅数据库中所有电流超过 10A 的记录。
### 准备数据
......@@ -208,64 +200,37 @@ taos> select * from meters where current > 10;
2020-08-15 12:20:00.000 | 12.20000 | 220 | 1 | Beijing.Chaoyang | 2 |
Query OK, 5 row(s) in set (0.004896s)
```
### 示例代码
### 示例程序
```java
public class SubscribeDemo {
private static final String topic = "topic-meter-current-bg-10";
private static final String sql = "select * from meters where current > 10";
public static void main(String[] args) {
Connection connection = null;
TSDBSubscribe subscribe = null;
try {
Class.forName("com.taosdata.jdbc.TSDBDriver");
Properties properties = new Properties();
properties.setProperty(TSDBDriver.PROPERTY_KEY_CHARSET, "UTF-8");
properties.setProperty(TSDBDriver.PROPERTY_KEY_TIME_ZONE, "UTC-8");
String jdbcUrl = "jdbc:TAOS://127.0.0.1:6030/power?user=root&password=taosdata";
connection = DriverManager.getConnection(jdbcUrl, properties);
subscribe = ((TSDBConnection) connection).subscribe(topic, sql, true); // 创建订阅
int count = 0;
while (count < 10) {
TimeUnit.SECONDS.sleep(1); // 等待1秒，避免频繁调用 consume，给服务端造成压力
TSDBResultSet resultSet = subscribe.consume(); // 消费数据
if (resultSet == null) {
continue;
}
ResultSetMetaData metaData = resultSet.getMetaData();
while (resultSet.next()) {
int columnCount = metaData.getColumnCount();
for (int i = 1; i <= columnCount; i++) {
System.out.print(metaData.getColumnLabel(i) + ": " + resultSet.getString(i) + "\t");
}
System.out.println();
count++;
}
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
if (null != subscribe)
subscribe.close(true); // 关闭订阅
if (connection != null)
connection.close();
} catch (SQLException throwables) {
throwables.printStackTrace();
}
}
}
}
```
<Tabs defaultValue="java" groupId="lang">
<TabItem label="Java" value="java">
<Java/>
</TabItem>
<TabItem label="Python" value="Python">
<Python/>
</TabItem>
<TabItem label="Go" value="go">
<Go/>
</TabItem>
<TabItem label="Rust" value="rust">
<Rust/>
</TabItem>
<TabItem label="Node.js" value="nodejs">
<Node/>
</TabItem>
<TabItem label="C#" value="csharp">
<CSharp/>
</TabItem>
<TabItem label="C" value="c">
<CDemo/>
</TabItem>
</Tabs>
运行示例程序，首先，它会消费符合查询条件的所有历史数据：
### 运行示例程序
示例程序会先消费符合查询条件的所有历史数据：
```bash
# java -jar subscribe.jar
ts: 1597464000000 current: 12.0 voltage: 220 phase: 1 location: Beijing.Chaoyang groupid : 2
ts: 1597464600000 current: 12.3 voltage: 220 phase: 2 location: Beijing.Chaoyang groupid : 2
ts: 1597465200000 current: 12.2 voltage: 220 phase: 1 location: Beijing.Chaoyang groupid : 2
......
docs-cn/08-advance-feature/_sub_c.mdx 0 → 100644
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```c
{{#include docs-examples/c/subscribe_demo.c}}
```
\ No newline at end of file
docs-cn/08-advance-feature/_sub_cs.mdx 0 → 100644
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```csharp
{{#include docs-examples/csharp/SubscribeDemo.cs}}
```
\ No newline at end of file
docs-cn/08-advance-feature/_sub_go.mdx 0 → 100644
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```go
{{#include docs-examples/go/sub/main.go}}
```
\ No newline at end of file
docs-cn/08-advance-feature/_sub_java.mdx 0 → 100644
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```java
{{#include docs-examples/java/src/main/java/com/taos/example/SubscribeDemo.java}}
```
:::note
目前 Java 接口没有提供异步订阅模式，但用户程序可以通过创建 `TimerTask` 等方式达到同样的效果。
:::
\ No newline at end of file
docs-cn/08-advance-feature/_sub_node.mdx 0 → 100644
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```js
{{#include docs-examples/node/nativeexample/subscribe_demo.js}}
```
\ No newline at end of file
docs-cn/08-advance-feature/_sub_python.mdx 0 → 100644
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```py
{{#include docs-examples/python/subscribe_demo.py}}
```
\ No newline at end of file
docs-cn/08-advance-feature/_sub_rust.mdx 0 → 100644
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```rs
{{#include docs-examples/rust/nativeexample/examples/subscribe_demo.rs}}
```
\ No newline at end of file
docs-examples/c/async_query_example.c 0 → 100644
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// compiple with:
// gcc -o async_query_example async_query_example.c -ltaos
// writing...
\ No newline at end of file
docs-examples/c/connect_example.c
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// compile with
// gcc connect_example.c -o connect_example -I /usr/local/taos/include -L /usr/local/taos/driver -ltaos
// gcc connect_example.c -o connect_example -ltaos
#include <stdio.h>
#include <stdlib.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 *host = "localhost";
const char *user = "root";
const char *passwd = "taosdata";
// if don't want to connect to a default db, set it to NULL or ""
const char *db = NULL;
TAOS *taos = taos_connect("localhost", "root", "taosdata", db, 6030);
printf("Connected\n");
taos_close(taos);
uint16_t port = 0; // 0 means use the default port
TAOS *taos = taos_connect(host, user, passwd, db, port);
if (taos == NULL) {
printf("failed to connect to server\n");
} else {
printf("connected\n");
taos_close(taos);
}
taos_cleanup();
}
docs-examples/c/insert_example.c 0 → 100644
浏览文件 @ 6d093c34
// compile with
// gcc -o insert_example insert_example.c -ltaos
#include <stdio.h>
#include <stdlib.h>
#include "taos.h"
/**
* @brief execute sql and print affected rows.
*
* @param taos
* @param sql
*/
void executeSQL(TAOS *taos, const char *sql) {
TAOS_RES *res = taos_query(taos, sql);
int code = taos_errno(res);
if (code != 0) {
printf("Error code: %d; Message: %s\n", code, taos_errstr(res));
taos_free_result(res);
taos_close(taos);
exit(EXIT_FAILURE);
}
int affectedRows = taos_affected_rows(res);
printf("affected rows %d\n", affectedRows);
taos_free_result(res);
}
int main() {
TAOS *taos = taos_connect("localhost", "root", "taosdata", NULL, 6030);
if (taos == NULL) {
printf("failed to connect to server\n");
exit(EXIT_FAILURE);
}
executeSQL(taos, "CREATE DATABASE power");
executeSQL(taos, "USE power");
executeSQL(taos, "CREATE STABLE meters (ts TIMESTAMP, current FLOAT, voltage INT, phase FLOAT) TAGS (location BINARY(64), groupId INT)");
executeSQL(taos, "INSERT INTO d1001 USING meters TAGS(Beijing.Chaoyang, 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 meters TAGS(Beijing.Chaoyang, 3) VALUES ('2018-10-03 14:38:16.650', 10.30000, 218, 0.25000)"
"d1003 USING meters TAGS(Beijing.Haidian, 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 meters TAGS(Beijing.Haidian, 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)");
taos_close(taos);
taos_cleanup();
}
// output:
// affected rows 0
// affected rows 0
// affected rows 0
// affected rows 8
\ No newline at end of file
docs-examples/c/json_protocol_example.c
浏览文件 @ 6d093c34
// compile with
// gcc connect_example.c -o connect_example -I /usr/local/taos/include -L /usr/local/taos/driver -ltaos
// gcc -o json_protocol_example json_protocol_example.c -ltaos
#include <stdio.h>
#include <stdlib.h>
#include <string.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));
void executeSQL(TAOS *taos, const char *sql) {
TAOS_RES *res = taos_query(taos, sql);
int code = taos_errno(res);
if (code != 0) {
printf("%s\n", taos_errstr(res));
taos_free_result(res);
taos_close(taos);
exit(EXIT_FAILURE);
}
taos_free_result(res);
}
// ANCHOR: main
int main() {
TAOS *taos = taos_connect("localhost", "root", "taosdata", "", 6030);
if (taos == NULL) {
printf("failed to connect to server\n");
exit(EXIT_FAILURE);
}
executeSQL(taos, "DROP DATABASE IF EXISTS test");
executeSQL(taos, "CREATE DATABASE test");
executeSQL(taos, "USE test");
char *line =
"[{\"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}}]";
char *lines[] = {line};
TAOS_RES *res = taos_schemaless_insert(taos, lines, 1, TSDB_SML_JSON_PROTOCOL, TSDB_SML_TIMESTAMP_NOT_CONFIGURED);
if (taos_errno(res) != 0) {
printf("failed to insert schema-less data, reason: %s\n", taos_errstr(res));
} else {
int affectedRow = taos_affected_rows(res);
printf("successfully inserted %d rows\n", affectedRow);
}
taos_free_result(res);
taos_close(taos);
taos_cleanup();
}
// output:
// successfully inserted 4 rows
// ANCHOR_END: main
docs-examples/c/line_example.c 0 → 100644
浏览文件 @ 6d093c34
// compile with
// gcc -o line_example line_example.c -ltaos
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "taos.h"
void executeSQL(TAOS *taos, const char *sql) {
TAOS_RES *res = taos_query(taos, sql);
int code = taos_errno(res);
if (code != 0) {
printf("%s\n", taos_errstr(res));
taos_free_result(res);
taos_close(taos);
exit(EXIT_FAILURE);
}
taos_free_result(res);
}
// ANCHOR: main
int main() {
TAOS *taos = taos_connect("localhost", "root", "taosdata", "", 0);
if (taos == NULL) {
printf("failed to connect to server\n");
exit(EXIT_FAILURE);
}
executeSQL(taos, "DROP DATABASE IF EXISTS test");
executeSQL(taos, "CREATE DATABASE test");
executeSQL(taos, "USE test");
char *lines[] = {"meters,location=Beijing.Haidian,groupid=2 current=11.8,voltage=221,phase=0.28 1648432611249",
"meters,location=Beijing.Haidian,groupid=2 current=13.4,voltage=223,phase=0.29 1648432611250",
"meters,location=Beijing.Haidian,groupid=3 current=10.8,voltage=223,phase=0.29 1648432611249",
"meters,location=Beijing.Haidian,groupid=3 current=11.3,voltage=221,phase=0.35 1648432611250"};
TAOS_RES *res = taos_schemaless_insert(taos, lines, 4, TSDB_SML_LINE_PROTOCOL, TSDB_SML_TIMESTAMP_MILLI_SECONDS);
if (taos_errno(res) != 0) {
printf("failed to insert schema-less data, reason: %s\n", taos_errstr(res));
} else {
int affectedRows = taos_affected_rows(res);
printf("successfully inserted %d rows\n", affectedRows);
}
taos_free_result(res);
taos_close(taos);
taos_cleanup();
}
// output:
// successfully inserted 4 rows
// ANCHOR_END: main
\ No newline at end of file
docs-examples/c/multi_bind_example.c 0 → 100644
浏览文件 @ 6d093c34
// compile with
// gcc -o multi_bind_example multi_bind_example.c -ltaos
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "taos.h"
/**
* @brief execute sql only and ignore result set
*
* @param taos
* @param sql
*/
void executeSQL(TAOS *taos, const char *sql) {
TAOS_RES *res = taos_query(taos, sql);
int code = taos_errno(res);
if (code != 0) {
printf("%s\n", taos_errstr(res));
taos_free_result(res);
taos_close(taos);
exit(EXIT_FAILURE);
}
taos_free_result(res);
}
/**
* @brief exit program when error occur.
*
* @param stmt
* @param code
* @param msg
*/
void checkErrorCode(TAOS_STMT *stmt, int code, const char *msg) {
if (code != 0) {
printf("%s. error: %s\n", msg, taos_stmt_errstr(stmt));
taos_stmt_close(stmt);
exit(EXIT_FAILURE);
}
}
/**
* @brief insert data using stmt API
*
* @param taos
*/
void insertData(TAOS *taos) {
// init
TAOS_STMT *stmt = taos_stmt_init(taos);
// prepare
const char *sql = "INSERT INTO ? USING meters TAGS(?, ?) values(?, ?, ?, ?)";
int code = taos_stmt_prepare(stmt, sql, 0);
checkErrorCode(stmt, code, "failed to execute taos_stmt_prepare");
// bind table name and tags
TAOS_BIND tags[2];
char *location = "Beijing.Chaoyang";
int groupId = 2;
tags[0].buffer_type = TSDB_DATA_TYPE_BINARY;
tags[0].buffer_length = strlen(location);
tags[0].length = &tags[0].buffer_length;
tags[0].buffer = location;
tags[0].is_null = NULL;
tags[1].buffer_type = TSDB_DATA_TYPE_INT;
tags[1].buffer_length = sizeof(int);
tags[1].length = &tags[1].buffer_length;
tags[1].buffer = &groupId;
tags[1].is_null = NULL;
code = taos_stmt_set_tbname_tags(stmt, "d1001", tags);
checkErrorCode(stmt, code, "failed to execute taos_stmt_set_tbname_tags");
// highlight-start
// insert two rows with multi binds
TAOS_MULTI_BIND params[4];
// values to bind
int64_t ts[] = {1648432611249, 1648432611749};
float current[] = {10.3, 12.6};
int voltage[] = {219, 218};
float phase[] = {0.31, 0.33};
// is_null array
char is_null[2] = {0};
// length array
int32_t int64Len[2] = {sizeof(int64_t)};
int32_t floatLen[2] = {sizeof(float)};
int32_t intLen[2] = {sizeof(int)};
params[0].buffer_type = TSDB_DATA_TYPE_TIMESTAMP;
params[0].buffer_length = sizeof(int64_t);
params[0].buffer = ts;
params[0].length = int64Len;
params[0].is_null = is_null;
params[0].num = 2;
params[1].buffer_type = TSDB_DATA_TYPE_FLOAT;
params[1].buffer_length = sizeof(float);
params[1].buffer = current;
params[1].length = floatLen;
params[1].is_null = is_null;
params[1].num = 2;
params[2].buffer_type = TSDB_DATA_TYPE_INT;
params[2].buffer_length = sizeof(int);
params[2].buffer = voltage;
params[2].length = intLen;
params[2].is_null = is_null;
params[2].num = 2;
params[3].buffer_type = TSDB_DATA_TYPE_FLOAT;
params[3].buffer_length = sizeof(float);
params[3].buffer = phase;
params[3].length = floatLen;
params[3].is_null = is_null;
params[3].num = 2;
code = taos_stmt_bind_param_batch(stmt, params); // bind batch
checkErrorCode(stmt, code, "failed to execute taos_stmt_bind_param_batch");
code = taos_stmt_add_batch(stmt); // add batch
checkErrorCode(stmt, code, "failed to execute taos_stmt_add_batch");
// highlight-end
// execute
code = taos_stmt_execute(stmt);
checkErrorCode(stmt, code, "failed to execute taos_stmt_execute");
int affectedRows = taos_stmt_affected_rows(stmt);
printf("successfully inserted %d rows\n", affectedRows);
// close
taos_stmt_close(stmt);
}
int main() {
TAOS *taos = taos_connect("localhost", "root", "taosdata", NULL, 6030);
if (taos == NULL) {
printf("failed to connect to server\n");
exit(EXIT_FAILURE);
}
executeSQL(taos, "DROP DATABASE IF EXISTS power");
executeSQL(taos, "CREATE DATABASE power");
executeSQL(taos, "USE power");
executeSQL(taos,
"CREATE STABLE meters (ts TIMESTAMP, current FLOAT, voltage INT, phase FLOAT) TAGS (location BINARY(64), "
"groupId INT)");
insertData(taos);
taos_close(taos);
taos_cleanup();
}
// output:
// successfully inserted 2 rows
\ No newline at end of file
docs-examples/c/query_example.c 0 → 100644
浏览文件 @ 6d093c34
// compile with:
// gcc -o query_example query_example.c -ltaos
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <taos.h>
typedef int16_t VarDataLenT;
#define TSDB_NCHAR_SIZE sizeof(int32_t)
#define VARSTR_HEADER_SIZE sizeof(VarDataLenT)
#define GET_FLOAT_VAL(x) (*(float *)(x))
#define GET_DOUBLE_VAL(x) (*(double *)(x))
#define varDataLen(v) ((VarDataLenT *)(v))[0]
int printRow(char *str, TAOS_ROW row, TAOS_FIELD *fields, int numFields) {
int len = 0;
char split = ' ';
for (int i = 0; i < numFields; ++i) {
if (i > 0) {
str[len++] = split;
}
if (row[i] == NULL) {
len += sprintf(str + len, "%s", "NULL");
continue;
}
switch (fields[i].type) {
case TSDB_DATA_TYPE_TINYINT:
len += sprintf(str + len, "%d", *((int8_t *)row[i]));
break;
case TSDB_DATA_TYPE_UTINYINT:
len += sprintf(str + len, "%u", *((uint8_t *)row[i]));
break;
case TSDB_DATA_TYPE_SMALLINT:
len += sprintf(str + len, "%d", *((int16_t *)row[i]));
break;
case TSDB_DATA_TYPE_USMALLINT:
len += sprintf(str + len, "%u", *((uint16_t *)row[i]));
break;
case TSDB_DATA_TYPE_INT:
len += sprintf(str + len, "%d", *((int32_t *)row[i]));
break;
case TSDB_DATA_TYPE_UINT:
len += sprintf(str + len, "%u", *((uint32_t *)row[i]));
break;
case TSDB_DATA_TYPE_BIGINT:
len += sprintf(str + len, "%" PRId64, *((int64_t *)row[i]));
break;
case TSDB_DATA_TYPE_UBIGINT:
len += sprintf(str + len, "%" PRIu64, *((uint64_t *)row[i]));
break;
case TSDB_DATA_TYPE_FLOAT: {
float fv = 0;
fv = GET_FLOAT_VAL(row[i]);
len += sprintf(str + len, "%f", fv);
} break;
case TSDB_DATA_TYPE_DOUBLE: {
double dv = 0;
dv = GET_DOUBLE_VAL(row[i]);
len += sprintf(str + len, "%lf", dv);
} break;
case TSDB_DATA_TYPE_BINARY:
case TSDB_DATA_TYPE_NCHAR: {
int32_t charLen = varDataLen((char *)row[i] - VARSTR_HEADER_SIZE);
memcpy(str + len, row[i], charLen);
len += charLen;
} break;
case TSDB_DATA_TYPE_TIMESTAMP:
len += sprintf(str + len, "%" PRId64, *((int64_t *)row[i]));
break;
case TSDB_DATA_TYPE_BOOL:
len += sprintf(str + len, "%d", *((int8_t *)row[i]));
default:
break;
}
}
return len;
}
/**
* @brief print column name and values of each row
*
* @param res
* @return int
*/
static int printResult(TAOS_RES *res) {
int numFields = taos_num_fields(res);
TAOS_FIELD *fields = taos_fetch_fields(res);
char header[256] = {0};
int len = 0;
for (int i = 0; i < numFields; ++i) {
len += sprintf(header + len, "%s ", fields[i].name);
}
puts(header);
TAOS_ROW row = NULL;
while ((row = taos_fetch_row(res))) {
char temp[256] = {0};
printRow(temp, row, fields, numFields);
puts(temp);
}
}
int main() {
TAOS *taos = taos_connect("localhost", "root", "taosdata", "power", 6030);
if (taos == NULL) {
puts("failed to connect to server");
exit(EXIT_FAILURE);
}
TAOS_RES *res = taos_query(taos, "SELECT * FROM meters LIMIT 2");
if (taos_errno(res) != 0) {
printf("failed to exeuce taos_query. error: %s\n", taos_errstr(res));
exit(EXIT_FAILURE);
}
printResult(res);
taos_free_result(res);
taos_close(taos);
taos_cleanup();
}
// output:
// ts current voltage phase location groupid
// 1648432611249 10.300000 219 0.310000 Beijing.Chaoyang 2
// 1648432611749 12.600000 218 0.330000 Beijing.Chaoyang 2
\ No newline at end of file
docs-examples/c/stmt_example.c 0 → 100644
浏览文件 @ 6d093c34
// compile with
// gcc -o stmt_example stmt_example.c -ltaos
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "taos.h"
/**
* @brief execute sql only.
*
* @param taos
* @param sql
*/
void executeSQL(TAOS *taos, const char *sql) {
TAOS_RES *res = taos_query(taos, sql);
int code = taos_errno(res);
if (code != 0) {
printf("%s\n", taos_errstr(res));
taos_free_result(res);
taos_close(taos);
exit(EXIT_FAILURE);
}
taos_free_result(res);
}
/**
* @brief check return status and exit program when error occur.
*
* @param stmt
* @param code
* @param msg
*/
void checkErrorCode(TAOS_STMT *stmt, int code, const char* msg) {
if (code != 0) {
printf("%s. error: %s\n", msg, taos_stmt_errstr(stmt));
taos_stmt_close(stmt);
exit(EXIT_FAILURE);
}
}
typedef struct {
int64_t ts;
float current;
int voltage;
float phase;
} Row;
/**
* @brief insert data using stmt API
*
* @param taos
*/
void insertData(TAOS *taos) {
// init
TAOS_STMT *stmt = taos_stmt_init(taos);
// prepare
const char *sql = "INSERT INTO ? USING meters TAGS(?, ?) VALUES(?, ?, ?, ?)";
int code = taos_stmt_prepare(stmt, sql, 0);
checkErrorCode(stmt, code, "failed to execute taos_stmt_prepare");
// bind table name and tags
TAOS_BIND tags[2];
char* location = "Beijing.Chaoyang";
int groupId = 2;
tags[0].buffer_type = TSDB_DATA_TYPE_BINARY;
tags[0].buffer_length = strlen(location);
tags[0].length = &tags[0].buffer_length;
tags[0].buffer = location;
tags[0].is_null = NULL;
tags[1].buffer_type = TSDB_DATA_TYPE_INT;
tags[1].buffer_length = sizeof(int);
tags[1].length = &tags[1].buffer_length;
tags[1].buffer = &groupId;
tags[1].is_null = NULL;
code = taos_stmt_set_tbname_tags(stmt, "d1001", tags);
checkErrorCode(stmt, code, "failed to execute taos_stmt_set_tbname_tags");
// insert two rows
Row rows[2] = {
{1648432611249, 10.3, 219, 0.31},
{1648432611749, 12.6, 218, 0.33},
};
TAOS_BIND values[4];
values[0].buffer_type = TSDB_DATA_TYPE_TIMESTAMP;
values[0].buffer_length = sizeof(int64_t);
values[0].length = &values[0].buffer_length;
values[0].is_null = NULL;
values[1].buffer_type = TSDB_DATA_TYPE_FLOAT;
values[1].buffer_length = sizeof(float);
values[1].length = &values[1].buffer_length;
values[1].is_null = NULL;
values[2].buffer_type = TSDB_DATA_TYPE_INT;
values[2].buffer_length = sizeof(int);
values[2].length = &values[2].buffer_length;
values[2].is_null = NULL;
values[3].buffer_type = TSDB_DATA_TYPE_FLOAT;
values[3].buffer_length = sizeof(float);
values[3].length = &values[3].buffer_length;
values[3].is_null = NULL;
for (int i = 0; i < 2; ++i) {
values[0].buffer = &rows[i].ts;
values[1].buffer = &rows[i].current;
values[2].buffer = &rows[i].voltage;
values[3].buffer = &rows[i].phase;
code = taos_stmt_bind_param(stmt, values); // bind param
checkErrorCode(stmt, code, "failed to execute taos_stmt_bind_param");
code = taos_stmt_add_batch(stmt); // add batch
checkErrorCode(stmt, code, "failed to execute taos_stmt_add_batch");
}
// execute
code = taos_stmt_execute(stmt);
checkErrorCode(stmt, code, "failed to execute taos_stmt_execute");
int affectedRows = taos_stmt_affected_rows(stmt);
printf("successfully inserted %d rows\n", affectedRows);
// close
taos_stmt_close(stmt);
}
int main() {
TAOS *taos = taos_connect("localhost", "root", "taosdata", NULL, 6030);
if (taos == NULL) {
printf("failed to connect to server\n");
exit(EXIT_FAILURE);
}
executeSQL(taos, "CREATE DATABASE power");
executeSQL(taos, "USE power");
executeSQL(taos, "CREATE STABLE meters (ts TIMESTAMP, current FLOAT, voltage INT, phase FLOAT) TAGS (location BINARY(64), groupId INT)");
insertData(taos);
taos_close(taos);
taos_cleanup();
}
// output:
// successfully inserted 2 rows
\ No newline at end of file
docs-examples/c/subscribe_demo.c 0 → 100644
浏览文件 @ 6d093c34
// compile with:
// gcc -o subscribe_demo subscribe_demo.c -ltaos
// writing...
docs-examples/c/telnet_line_example.c 0 → 100644
浏览文件 @ 6d093c34
// compile with
// gcc -o telnet_line_example telnet_line_example.c -ltaos
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "taos.h"
void executeSQL(TAOS *taos, const char *sql) {
TAOS_RES *res = taos_query(taos, sql);
int code = taos_errno(res);
if (code != 0) {
printf("%s\n", taos_errstr(res));
taos_free_result(res);
taos_close(taos);
exit(EXIT_FAILURE);
}
taos_free_result(res);
}
// ANCHOR: main
int main() {
TAOS *taos = taos_connect("localhost", "root", "taosdata", "", 6030);
if (taos == NULL) {
printf("failed to connect to server\n");
exit(EXIT_FAILURE);
}
executeSQL(taos, "DROP DATABASE IF EXISTS test");
executeSQL(taos, "CREATE DATABASE test");
executeSQL(taos, "USE test");
char *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",
};
TAOS_RES *res = taos_schemaless_insert(taos, lines, 8, TSDB_SML_TELNET_PROTOCOL, TSDB_SML_TIMESTAMP_NOT_CONFIGURED);
if (taos_errno(res) != 0) {
printf("failed to insert schema-less data, reason: %s\n", taos_errstr(res));
} else {
int affectedRow = taos_affected_rows(res);
printf("successfully inserted %d rows\n", affectedRow);
}
taos_free_result(res);
taos_close(taos);
taos_cleanup();
}
// output:
// successfully inserted 8 rows
// ANCHOR_END: main
docs-examples/csharp/SubscribeDemo.cs 0 → 100644
浏览文件 @ 6d093c34
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace csharp
{
internal class SubscribeDemo
{
}
}
docs-examples/go/sub/main.go
浏览文件 @ 6d093c34
......@@ -48,4 +48,6 @@ func main() {
}
}()
}
}
\ No newline at end of file
}
// 未完成
docs-examples/java/src/main/java/com/taos/example/SubscribeDemo.java 0 → 100644
浏览文件 @ 6d093c34
package com.taos.example;
import com.taosdata.jdbc.TSDBConnection;
import com.taosdata.jdbc.TSDBDriver;
import com.taosdata.jdbc.TSDBResultSet;
import com.taosdata.jdbc.TSDBSubscribe;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.Properties;
import java.util.concurrent.TimeUnit;
public class SubscribeDemo {
private static final String topic = "topic-meter-current-bg-10";
private static final String sql = "select * from meters where current > 10";
public static void main(String[] args) {
Connection connection = null;
TSDBSubscribe subscribe = null;
try {
Class.forName("com.taosdata.jdbc.TSDBDriver");
Properties properties = new Properties();
properties.setProperty(TSDBDriver.PROPERTY_KEY_CHARSET, "UTF-8");
properties.setProperty(TSDBDriver.PROPERTY_KEY_TIME_ZONE, "UTC-8");
String jdbcUrl = "jdbc:TAOS://127.0.0.1:6030/power?user=root&password=taosdata";
connection = DriverManager.getConnection(jdbcUrl, properties);
subscribe = ((TSDBConnection) connection).subscribe(topic, sql, true); // 创建订阅
int count = 0;
while (count < 10) {
TimeUnit.SECONDS.sleep(1); // 等待1秒，避免频繁调用 consume，给服务端造成压力
TSDBResultSet resultSet = subscribe.consume(); // 消费数据
if (resultSet == null) {
continue;
}
ResultSetMetaData metaData = resultSet.getMetaData();
while (resultSet.next()) {
int columnCount = metaData.getColumnCount();
for (int i = 1; i <= columnCount; i++) {
System.out.print(metaData.getColumnLabel(i) + ": " + resultSet.getString(i) + "\t");
}
System.out.println();
count++;
}
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
if (null != subscribe)
subscribe.close(true); // 关闭订阅
if (connection != null)
connection.close();
} catch (SQLException throwables) {
throwables.printStackTrace();
}
}
}
}
\ No newline at end of file
docs-examples/node/nativeexample/subscribe_demo.js 0 → 100644
浏览文件 @ 6d093c34
const taos = require("td2.0-connector");
const conn = taos.connect({ host: "localhost", database: "power" });
// 未完成
\ No newline at end of file
docs-examples/python/subscribe_demo.py 0 → 100644
浏览文件 @ 6d093c34
import taos
\ No newline at end of file
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