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# ODBC
在 JDBC 插件的基础上，IoTDB 可以通过 ODBC-JDBC 桥来支持通过 ODBC 对数据库的操作。

## 依赖
* 带依赖打包的 IoTDB JDBC 插件包
* ODBC-JDBC 桥（如 Zappy-Sys）

## 部署方法
### 准备 JDBC 插件包
下载 IoTDB 源码，在根目录下执行下面的命令：
```shell
mvn clean package -pl iotdb-client/jdbc -am -DskipTests -P get-jar-with-dependencies
```
之后，就可以在`iotdb-client/jdbc/target`目录下看到`iotdb-jdbc-1.3.2-SNAPSHOT-jar-with-dependencies.jar`文件。

### 准备 ODBC-JDBC 桥
*注意: 这里给出的仅仅是一种 ODBC-JDBC 桥，仅作示例。读者可以自行寻找其他的 ODBC-JDBC 桥来对接 IoTDB 的 JDBC 插件。*
1.  **下载 Zappy-Sys ODBC-JDBC 桥插件**：
    进入 https://zappysys.com/products/odbc-powerpack/odbc-jdbc-bridge-driver/ 网站，点击下载按钮并直接安装。

    ![ZappySys_website.jpg](/img/ZappySys_website.jpg)

2. **准备 IoTDB**：打开 IoTDB 集群，并任意写入一条数据。
    ```sql
    IoTDB > insert into root.ln.wf02.wt02(timestamp,status) values(1,true)
    ```

3. **部署及调试插件**：
    1. 打开 ODBC 数据源 32/64 位，取决于 Windows 的位数，一个示例的位置是 `C:\ProgramData\Microsoft\Windows\Start Menu\Programs\Administrative Tools`。

       ![ODBC_ADD_CN.jpg](/img/ODBC_ADD_CN.jpg)

    2. 点击添加，选择 ZappySys JDBC Bridge。

       ![ODBC_CREATE_CN.jpg](/img/ODBC_CREATE_CN.jpg)

    3. 填写如下配置：

       | 配置项                 | 填写内容                                          | 示例                                                                                                                 |
       |---------------------|-----------------------------------------------|--------------------------------------------------------------------------------------------------------------------|
       | Connection String   | jdbc:iotdb://<IoTDB 的 IP>:<IoTDB 的 rpc port>/ | jdbc:iotdb://127.0.0.1:6667/                                                                                       |
       | Driver Class        | org.apache.iotdb.jdbc.IoTDBDriver             | org.apache.iotdb.jdbc.IoTDBDriver                                                                                  |
       | JDBC driver file(s) | IoTDB JDBC jar-with-dependencies 插件路径         | C:\Users\13361\Documents\GitHub\iotdb\iotdb-client\jdbc\target\iotdb-jdbc-1.3.2-SNAPSHOT-jar-with-dependencies.jar |
       | User name           | IoTDB 的用户名                                    | root                                                                                                               |
       | User password       | IoTDB 的密码                                     | root                                                                                                               |

       ![ODBC_CONNECTION.png](/img/ODBC_CONNECTION.png)

    4. 点击 Test Connection 按钮，应该显示连接成功。

       ![ODBC_CONFIG_CN.jpg](/img/ODBC_CONFIG_CN.jpg)

    5. 点击上方的 Preview， 将查询文本换为 `select * from root.**`，点击 Preview Data，应该正确显示查询结果。

       ![ODBC_TEST.jpg](/img/ODBC_TEST.jpg)

4. **使用 ODBC 操作数据**：正确部署后，就可以使用 Windows 的 ODBC 库，对 IoTDB 的数据进行操作。 这里给出 C# 语言的代码示例：
    ```C#
    using System.Data.Odbc;
    
    // Get a connection
    var dbConnection = new OdbcConnection("DSN=ZappySys JDBC Bridge");
    dbConnection.Open();
    
    // Execute the write commands to prepare data
    var dbCommand = dbConnection.CreateCommand();
    dbCommand.CommandText = "insert into root.Keller.Flur.Energieversorgung(time, s1) values(1715670861634, 1)";
    dbCommand.ExecuteNonQuery();
    dbCommand.CommandText = "insert into root.Keller.Flur.Energieversorgung(time, s2) values(1715670861634, true)";
    dbCommand.ExecuteNonQuery();
    dbCommand.CommandText = "insert into root.Keller.Flur.Energieversorgung(time, s3) values(1715670861634, 3.1)";
    dbCommand.ExecuteNonQuery();
    
    // Execute the read command
    dbCommand.CommandText = "SELECT * FROM root.Keller.Flur.Energieversorgung";
    var dbReader = dbCommand.ExecuteReader();
    
    // Write the output header
    var fCount = dbReader.FieldCount;
    Console.Write(":");
    for(var i = 0; i < fCount; i++)
    {
        var fName = dbReader.GetName(i);
        Console.Write(fName + ":");
    }
    Console.WriteLine();
    
    // Output the content
    while (dbReader.Read())
    {
        Console.Write(":");
        for(var i = 0; i < fCount; i++) 
        {
            var fieldType = dbReader.GetFieldType(i);
            switch (fieldType.Name)
            {
                case "DateTime":
                    var dateTime = dbReader.GetInt64(i);
                    Console.Write(dateTime + ":");
                    break;
                case "Double":
                    if (dbReader.IsDBNull(i)) 
                    {
                        Console.Write("null:");
                    }
                    else 
                    {
                        var fValue = dbReader.GetDouble(i);
                        Console.Write(fValue + ":");
                    }   
                    break;
                default:
                    Console.Write(fieldType.Name + ":");
                    break;
            }
        }
        Console.WriteLine();
    }
    
    // Shut down gracefully
    dbReader.Close();
    dbCommand.Dispose();
    dbConnection.Close();
    ```
   运行该程序可以向 IoTDB 内写入数据，并且查询并打印写入的数据。