Examples of Using C++ Driver

A C++ sample NuoDB application can be found in NUODB_HOME/samples/doc/cpp. The application is called HelloDB and it incorporates the code from the examples in Database Operations Using C++ Driver.

The application can be built by using the platform’s corresponding build script:

Platform Script

Linux

build-linux.sh

Windows

build-windows.bat

HelloDB will open a database whose name is passed in as a command line argument. The constructor creates a connection to the database as user “dba” and password “goalie”. The createTable() method creates a table called NAMES, with two columns, an integer ID that is always generated and a string NAME. The addNames() method generates names and adds them to the NAMES table. The method getName() queries the NAMES table to get a NAME based on the given ID.

Here is the include file, HelloDB.h, used by HelloDB.cpp below:

HelloDB.h

/*
 * A simple class that connects to a NuoDB server. It uses some of the
 * basic connection methods to create a table and insert or fetch rows.
 */
class HelloDB
{
public:
    HelloDB(const char* dbName) throw (SQLException);
    ~HelloDB();
    void        createTable() throw (SQLException);
    void        addNames() throw (SQLException);
    const char* getName(int id) throw (SQLException);
private:
    Connection* connection;
};

HelloDB.cpp

Here is the full HelloDB.cpp example.

/*
 * An introductory program that shows how to establish a connection with
 * a NuoDB server and execute a few basic SQL commands.
 */
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include "NuoDB.h"

using namespace NuoDB;
#include "HelloDB.h"
/*
 * Creates an instance of HelloDB connected to the database with
 * the given name on the localhost. This example class uses the
 * default testing name & password.
 */
HelloDB::HelloDB(const char* dbName) throw (SQLException)
{
    connection = Connection::create(
                    dbName,
                    "dba",                  // username
                    "goalie",               // password
                    1,                      // number of properties
                    "schema", "hello" );    // schema=hello property
}
/*
 * Closes the connection.
 */
HelloDB::~HelloDB()
{
    connection->close();
}
/*
 * Creates a testing table named "names" which maps integer identifiers
 * to names.
 */
void HelloDB::createTable() throw (SQLException)
{
    Statement* stmt = connection->createStatement();
    try {
        stmt->execute(
            "create table names ("
                "id int generated always as identity primary key, "
                "name string)" );
        connection->commit();
        stmt->close();
        printf("The table 'NAMES' was created.\n");
    } catch (SQLException& xcp) {
        connection->rollback();
        printf("The table 'NAMES' already exists, re-using it.\n");
    }
}
/*
 * Adds an identifier-to-name mapping in the "names" table.
 */
void HelloDB::addNames() throw (SQLException)
{
    PreparedStatement* stmt = connection->prepareStatement(
            "insert into names (name) values (?)",
            NuoDB::RETURN_GENERATED_KEYS );
    try {
        for (int i = 1; i <= 15; i++) {
            char name[100];
            sprintf(name, "Fred # %d", i);
            stmt->setString(1, name);
            int updateCount = stmt->executeUpdate();
        }
        ResultSet*          resultSet = stmt->getGeneratedKeys();
        ResultSetMetaData*  resultSetMetaData = resultSet->getMetaData();
        const char*         columnName = resultSetMetaData->getColumnName(1);
        while (resultSet->next()) {
            printf(
                "New id=%d for column %s\n",
                resultSet->getInt(1),
                columnName );
        }
        connection->commit();
        resultSet->close();
        stmt->close();
    } catch (SQLException& xcp) {
        connection->rollback();
        throw;
    }
}
/*
 * Gets the name mapped to the given identifier. Returns NULL if there
 * is no such identifier in the table.
 */
const char* HelloDB::getName(int id) throw (SQLException)
{
    PreparedStatement* stmt =
        connection->prepareStatement("select name from names where id=?");
    stmt->setInt(1, id);
    ResultSet*  rs = stmt->executeQuery();
    char*       name;
    if (rs->next()) {
        name = new char[strlen(rs->getString(1)) + 1];
        strcpy(name, rs->getString(1));
    } else {
        name = NULL;
    }
    rs->close();
    stmt->close();
    return name;
}

int main(int argc, char** argv)
{
    if (argc != 2) {
        printf("Usage: %s <dbname>\n", argv[0]);
        return -1;
    }
    try {
        HelloDB helloDB(argv[1]);
        helloDB.createTable();
        helloDB.addNames();
        const char* name = helloDB.getName(12);
        printf("The NAME with id of 12 is '%s'\n", name);
        delete[] name;
    } catch (SQLException& xcp) {
        printf("Got exception: %s\n", xcp.getText());
        return -1;
    }
    return 0;
}