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# ODBC
With IoTDB JDBC, IoTDB can be accessed using the ODBC-JDBC bridge.

## 1. Dependencies
* IoTDB-JDBC's jar-with-dependency package
* ODBC-JDBC bridge (e.g. ZappySys JDBC Bridge)

## 2. Deployment
### 2.1 Preparing JDBC package
Download the source code of IoTDB, and execute the following command in root directory:
```shell
mvn clean package -pl iotdb-client/jdbc -am -DskipTests -P get-jar-with-dependencies
```
Then, you can see the output `iotdb-jdbc-1.3.2-SNAPSHOT-jar-with-dependencies.jar` under `iotdb-client/jdbc/target` directory.

### 2.2 Preparing ODBC-JDBC Bridge
*Note: Here we only provide one kind of ODBC-JDBC bridge as the instance. Readers can use other ODBC-JDBC bridges to access IoTDB with the IOTDB-JDBC.*
1.  **Download Zappy-Sys ODBC-JDBC Bridge**:
    Enter the https://zappysys.com/products/odbc-powerpack/odbc-jdbc-bridge-driver/ website, and click "download".

    ![ZappySys_website.jpg](/img/ZappySys_website.jpg)

2. **Prepare IoTDB**: Set up IoTDB cluster, and write a row of data arbitrarily.
    ```sql
    IoTDB > insert into root.ln.wf02.wt02(timestamp,status) values(1,true)
    ```

3. **Deploy and Test the Bridge**:
    1. Open ODBC Data Sources(32/64 bit), depending on the bits of Windows. One possible position is `C:\ProgramData\Microsoft\Windows\Start Menu\Programs\Administrative Tools`.

       ![ODBC_ADD_EN.jpg](/img/ODBC_ADD_EN.jpg)

    2. Click on "add" and select ZappySys JDBC Bridge.

       ![ODBC_CREATE_EN.jpg](/img/ODBC_CREATE_EN.jpg)

    3. Fill in the following settings:

       | Property            | Content                                                   | Example                                                                                                            |
       |---------------------|-----------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------|
       | Connection String   | jdbc:iotdb://\<The IP of IoTDB>:\<The rpc port of IoTDB>/ | jdbc:iotdb://127.0.0.1:6667/                                                                                       |
       | Driver Class        | org.apache.iotdb.jdbc.IoTDBDriver                         | org.apache.iotdb.jdbc.IoTDBDriver                                                                                  |
       | JDBC driver file(s) | The path of IoTDB JDBC jar-with-dependencies              | C:\Users\13361\Documents\GitHub\iotdb\iotdb-client\jdbc\target\iotdb-jdbc-1.3.2-SNAPSHOT-jar-with-dependencies.jar |
       | User name           | IoTDB's user name                                         | root                                                                                                               |
       | User password       | IoTDB's password                                          | root                                                                                                               |

       ![ODBC_CONNECTION.png](/img/ODBC_CONNECTION.png)

    4. Click on "Test Connection" button, and a "Test Connection: SUCCESSFUL" should appear.

       ![ODBC_CONFIG_EN.jpg](/img/ODBC_CONFIG_EN.jpg)

    5. Click the "Preview" button above, and replace the original query text with `select * from root.**`, then click "Preview Data", and the query result should correctly.

       ![ODBC_TEST.jpg](/img/ODBC_TEST.jpg)

4. **Operate IoTDB's data with ODBC**: After correct deployment, you can use Microsoft's ODBC library to operate IoTDB's data. Here's an example written in C#:
    ```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();
    ```
   This program can write data into IoTDB, and query the data we have just written.