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# C++ Native API

## Dependencies
- Java 8+
- Maven 3.5+
- Flex
- Bison 2.7+
- Boost 1.56+
- OpenSSL 1.0+
- GCC 5.5.0+


## Installation From Source Code

### Install CPP Dependencies

- **MAC**

    1. Install Bison ：Bison 2.3 is preinstalled on OSX, but this version is too low.

       When building Thrift with Bison 2.3, the following error would pop out:
       ```invalid directive: '%code'```

       For such case, please update `Bison`:
       ```shell
       brew install bison
       brew link bison --force
       ```
       
       Then, you need to tell the OS where the new bison is.
    
          For Bash users:
          ```shell
          echo 'export PATH="/usr/local/opt/bison/bin:$PATH"' >> ~/.bash_profile
          ```

          For zsh users:
          ```shell
          echo 'export PATH="/usr/local/opt/bison/bin:$PATH"' >> ~/.zshrc
          ```

    2. Install Boost ：Please make sure a relative new version of Boost is ready on your machine.
       If no Boost available, install the latest version of Boost:
          ```shell
          brew install boost
          brew link boost
          ```

    3. OpenSSL ：Make sure the Openssl libraries has been install on your Mac. The default Openssl include file search path is "/usr/local/opt/openssl/include".

       If Openssl header files can not be found when building Thrift, please add option`-Dopenssl.include.dir=""`.


- **Ubuntu 20**

  To install all dependencies, run:

    ```shell
    sudo apt-get install gcc-9 g++-9 libstdc++-9-dev bison flex libboost-all-dev libssl-dev zlib1g-dev
    ```


- **CentOS 7.x**

  Some packages can be installed using Yum:

    ```shell
    sudo yum install bison flex openssl-devel
    ```

  The version of gcc and boost installed by yum is too low, therefore you should compile or download these binary packages by yourself.


- **Windows**

    1. Building environment
        * Install `MS Visual Studio`(recommend 2019 version): remember to install Visual Studio C/C++ IDE and compiler(supporting CMake, Clang, MinGW).
        * Download and install [CMake](https://cmake.org/download/) .

    2. Download and install `Flex` & `Bison`
        * Download [Win_Flex_Bison](https://sourceforge.net/projects/winflexbison/) .
        * After downloaded, please rename the executables to `flex.exe` and `bison.exe` and add them to "PATH" environment variables.

    3. Install `Boost`
        * Download [Boost](https://www.boost.org/users/download/) .
        * Then build `Boost` by executing bootstrap.bat and b2.exe.

    4. Install `OpenSSL`
        * Download and install [OpenSSL](http://slproweb.com/products/Win32OpenSSL.html) .


### Compile

You can download the source code from:
```shell
git clone https://github.com/apache/iotdb.git
```

The default dev branch is the master branch, If you want to use a released version (eg. `rel/0.13`):
```shell
git checkout rel/0.13
```

Under the root path of iotdb:

- Mac & Linux
    ```shell
    mvn package -P compile-cpp -pl example/client-cpp-example -am -DskipTest
    ```

- Windows
    ```shell
    mvn package -P compile-cpp -pl client-cpp,server,example/client-cpp-example -am -Dcmake.generator="your cmake generator" -Dboost.include.dir=${your boost header folder} -Dboost.library.dir=${your boost lib (stage) folder} -DskipTests
    ```
    - When building client-cpp project, use `-Dcmake.generator=""` option to specify a Cmake generator. E.g. `-Dcmake.generator="Visual Studio 16 2019"` (`cmake --help` shows a long list of supported Cmake generators.)
    - To help CMake find your Boost libraries on windows, you should set `-DboostIncludeDir="C:\Program Files (x86)\boost_1_78_0" -DboostLibraryDir="C:\Program Files (x86)\boost_1_78_0\stage\lib"` to your mvn build command.
    ``

If the compilation finishes successfully, the packaged zip file will be placed under `client-cpp/target/client-cpp-1.1.0-SNAPSHOT-cpp-${os}.zip`


## Native APIs

Here we show the commonly used interfaces and their parameters in the Native API:

### Initialization

- Open a Session
```cpp
void open(); 
```

- Open a session, with a parameter to specify whether to enable RPC compression
```cpp
void open(bool enableRPCCompression); 
```
Notice: this RPC compression status of client must comply with that of IoTDB server

- Close a Session
```cpp
void close(); 
```

### Data Definition Interface (DDL)

#### Database Management

- CREATE DATABASE
```cpp
void setStorageGroup(const std::string &storageGroupId);
```

- Delete one or several databases
```cpp
void deleteStorageGroup(const std::string &storageGroup);
void deleteStorageGroups(const std::vector<std::string> &storageGroups);
```

#### Timeseries Management

- Create one or multiple timeseries
```cpp
void createTimeseries(const std::string &path, TSDataType::TSDataType dataType, TSEncoding::TSEncoding encoding,
                          CompressionType::CompressionType compressor);
                          
void createMultiTimeseries(const std::vector<std::string> &paths,
                           const std::vector<TSDataType::TSDataType> &dataTypes,
                           const std::vector<TSEncoding::TSEncoding> &encodings,
                           const std::vector<CompressionType::CompressionType> &compressors,
                           std::vector<std::map<std::string, std::string>> *propsList,
                           std::vector<std::map<std::string, std::string>> *tagsList,
                           std::vector<std::map<std::string, std::string>> *attributesList,
                           std::vector<std::string> *measurementAliasList);
```

- Create aligned timeseries
```cpp
void createAlignedTimeseries(const std::string &deviceId,
                             const std::vector<std::string> &measurements,
                             const std::vector<TSDataType::TSDataType> &dataTypes,
                             const std::vector<TSEncoding::TSEncoding> &encodings,
                             const std::vector<CompressionType::CompressionType> &compressors);
```

- Delete one or several timeseries
```cpp
void deleteTimeseries(const std::string &path);
void deleteTimeseries(const std::vector<std::string> &paths);
```

- Check whether the specific timeseries exists.
```cpp
bool checkTimeseriesExists(const std::string &path);
```

#### Schema Template

- Create a schema template
```cpp
void createSchemaTemplate(const Template &templ);
```

- Set the schema template named `templateName` at path `prefixPath`.
```cpp
void setSchemaTemplate(const std::string &template_name, const std::string &prefix_path);
```

- Unset the schema template
```cpp
void unsetSchemaTemplate(const std::string &prefix_path, const std::string &template_name);
```

- After measurement template created, you can edit the template with belowed APIs.
```cpp
// Add aligned measurements to a template
void addAlignedMeasurementsInTemplate(const std::string &template_name,
                                      const std::vector<std::string> &measurements,
                                      const std::vector<TSDataType::TSDataType> &dataTypes,
                                      const std::vector<TSEncoding::TSEncoding> &encodings,
                                      const std::vector<CompressionType::CompressionType> &compressors);

// Add one aligned measurement to a template
void addAlignedMeasurementsInTemplate(const std::string &template_name,
                                      const std::string &measurement,
                                      TSDataType::TSDataType dataType,
                                      TSEncoding::TSEncoding encoding,
                                      CompressionType::CompressionType compressor);

// Add unaligned measurements to a template
void addUnalignedMeasurementsInTemplate(const std::string &template_name,
                                        const std::vector<std::string> &measurements,
                                        const std::vector<TSDataType::TSDataType> &dataTypes,
                                        const std::vector<TSEncoding::TSEncoding> &encodings,
                                        const std::vector<CompressionType::CompressionType> &compressors);

// Add one unaligned measurement to a template
void addUnalignedMeasurementsInTemplate(const std::string &template_name,
                                        const std::string &measurement,
                                        TSDataType::TSDataType dataType,
                                        TSEncoding::TSEncoding encoding,
                                        CompressionType::CompressionType compressor);

// Delete a node in template and its children
void deleteNodeInTemplate(const std::string &template_name, const std::string &path);
```

- You can query measurement templates with these APIS:
```cpp
// Return the amount of measurements inside a template
int countMeasurementsInTemplate(const std::string &template_name);

// Return true if path points to a measurement, otherwise returne false
bool isMeasurementInTemplate(const std::string &template_name, const std::string &path);

// Return true if path exists in template, otherwise return false
bool isPathExistInTemplate(const std::string &template_name, const std::string &path);

// Return all measurements paths inside template
std::vector<std::string> showMeasurementsInTemplate(const std::string &template_name);

// Return all measurements paths under the designated patter inside template
std::vector<std::string> showMeasurementsInTemplate(const std::string &template_name, const std::string &pattern);
```


### Data Manipulation Interface (DML)

#### Insert

> It is recommended to use insertTablet to help improve write efficiency.

- Insert a Tablet，which is multiple rows of a device, each row has the same measurements
    - Better Write Performance
    - Support null values: fill the null value with any value, and then mark the null value via BitMap
```cpp
void insertTablet(Tablet &tablet);
```

- Insert multiple Tablets
```cpp
void insertTablets(std::unordered_map<std::string, Tablet *> &tablets);
```

- Insert a Record, which contains multiple measurement value of a device at a timestamp
```cpp
void insertRecord(const std::string &deviceId, int64_t time, const std::vector<std::string> &measurements,
                  const std::vector<TSDataType::TSDataType> &types, const std::vector<char *> &values);
```

- Insert multiple Records
```cpp
void insertRecords(const std::vector<std::string> &deviceIds,
                   const std::vector<int64_t> &times,
                   const std::vector<std::vector<std::string>> &measurementsList,
                   const std::vector<std::vector<TSDataType::TSDataType>> &typesList,
                   const std::vector<std::vector<char *>> &valuesList);
```

- Insert multiple Records that belong to the same device. With type info the server has no need to do type inference, which leads a better performance
```cpp
void insertRecordsOfOneDevice(const std::string &deviceId,
                              std::vector<int64_t> &times,
                              std::vector<std::vector<std::string>> &measurementsList,
                              std::vector<std::vector<TSDataType::TSDataType>> &typesList,
                              std::vector<std::vector<char *>> &valuesList);
```

#### Insert with type inference

Without type information, server has to do type inference, which may cost some time.

```cpp
void insertRecord(const std::string &deviceId, int64_t time, const std::vector<std::string> &measurements,
                  const std::vector<std::string> &values);


void insertRecords(const std::vector<std::string> &deviceIds,
                   const std::vector<int64_t> &times,
                   const std::vector<std::vector<std::string>> &measurementsList,
                   const std::vector<std::vector<std::string>> &valuesList);


void insertRecordsOfOneDevice(const std::string &deviceId,
                              std::vector<int64_t> &times,
                              std::vector<std::vector<std::string>> &measurementsList,
                              const std::vector<std::vector<std::string>> &valuesList);
```

#### Insert data into Aligned Timeseries

The Insert of aligned timeseries uses interfaces like `insertAlignedXXX`, and others are similar to the above interfaces:

- insertAlignedRecord
- insertAlignedRecords
- insertAlignedRecordsOfOneDevice
- insertAlignedTablet
- insertAlignedTablets

#### Delete

- Delete data before or equal to a timestamp of one or several timeseries
```cpp
void deleteData(const std::string &path, int64_t time);
void deleteData(const std::vector<std::string> &deviceId, int64_t time);
```

### IoTDB-SQL Interface

- Execute query statement
```cpp
unique_ptr<SessionDataSet> executeQueryStatement(const std::string &sql);
```

- Execute non query statement
```cpp
void executeNonQueryStatement(const std::string &sql);
```


## Examples

The sample code of using these interfaces is in:

- `example/client-cpp-example/src/SessionExample.cpp`
- `example/client-cpp-example/src/AlignedTimeseriesSessionExample.cpp` （使用对齐时间序列）

If the compilation finishes successfully, the example project will be placed under `example/client-cpp-example/target`

## FAQ

### on Mac

If errors occur when compiling thrift source code, try to downgrade your xcode-commandline from 12 to 11.5

see https://stackoverflow.com/questions/63592445/ld-unsupported-tapi-file-type-tapi-tbd-in-yaml-file/65518087#65518087


### on Windows

When Building Thrift and downloading packages via "wget", a possible annoying issue may occur with
error message looks like:
```shell
Failed to delete cached file C:\Users\Administrator\.m2\repository\.cache\download-maven-plugin\index.ser
```
Possible fixes:
- Try to delete the ".m2\repository\\.cache\" directory and try again.
- Add "\<skipCache>true\</skipCache>" configuration to the download-maven-plugin maven phase that complains this error.