Connect an application

Prerequisites

The tutorial assumes that you have:

  • installed YugabyteDB, and created a universe with YSQL enabled. If not, please follow the steps in Quick start.
  • have a 32-bit (x86) or 64-bit (x64) architecture machine.
  • have gcc 4.1.2 or later, clang 3.4 or later installed.

Install the libpqxx driver

Download the source from the libpqxx and build the binaries as follows. If needed, detailed steps are provided in the README file.

Get the source

$ git clone https://github.com/jtv/libpqxx.git

Dependencies

Note that this package depends on PostgreSQL binaries. Make sure that the PostgreSQL bin directory is on the command path.

export PATH=$PATH:<yugabyte-install-dir>/postgres/bin

Build and install

$ cd libpqxx
$ ./configure
$ make
$ make install

Create a sample C++ application

Add the C++ code

Create a file ybsql_hello_world.cpp and copy the contents below:

#include <iostream>
#include <pqxx/pqxx>

int main(int, char *argv[])
{
  pqxx::connection c("host=127.0.0.1 port=5433 dbname=yugabyte user=yugabyte password=yugabyte");
  pqxx::work txn(c);
  pqxx::result r;

  /* Create table */
  try
  {
    r = txn.exec("CREATE TABLE employee (id int PRIMARY KEY, \
                  name varchar, age int, \
                  language varchar)");
  }
  catch (const std::exception &e)
  {
    std::cerr << e.what() << std::endl;
    return 1;
  }

  std::cout << "Created table employee\n";

  /* Insert a row */
  try
  {
    r = txn.exec("INSERT INTO employee (id, name, age, language) \
                  VALUES (1, 'John', 35, 'C++')");
  }
  catch (const std::exception &e)
  {
    std::cerr << e.what() << std::endl;
    return 1;
  }

  std::cout << "Inserted data (1, 'John', 35, 'C++')\n";

  /* Query the row */
  try
  {
    r = txn.exec("SELECT name, age, language FROM employee WHERE id = 1");

    for (auto row: r)
      std::cout << "Query returned: "
          << row["name"].c_str() << ", "
          << row["age"].as<int>() << ", "
          << row["language"].c_str() << std::endl;
  }
  catch (const std::exception &e)
  {
    std::cerr << e.what() << std::endl;
    return 1;
  }

  txn.commit();
  return 0;
}

Run the application

You can compile the file using gcc or clang. Note that C++ 11 is the minimum supported C++ version. Make sure your compiler supports this, and if necessary, that you have support for C++11 configured. For gcc, run the following command:

$ g++ -std=c++11 ybsql_hello_world.cpp -lpqxx -lpq -I<yugabyte-install-dir>/postgres/include -o ybsql_hello_world

Use the application by running the following command:

$ ./ybsql_hello_world

You should see the following output:

Created table employee
Inserted data (1, 'John', 35, 'C++')
Query returned: John, 35, C++