mysql++11

Description:

This is a lightweight wrapper for MySQL with simple and convenient usage in Modern C++ (C++11, C++14, C++17 or later).

License:

Completely free. No restriction!

Requirements:

C++11 ready compiler - please check if your compiler is up to date (at the moment: MSVC 2012, g++ 5.1, clang 3.8)
MySQL Connector/C:
- For Windows: https://dev.mysql.com/downloads/connector/c/
- For Linux: sudo apt-get install libmysqlclient
No .cpp, no compiled library, no binary needed

Credits:

sqlite::utility::function_traits is from @github/aminroosta/sqlite_modern_cpp: https://github.com/aminroosta/sqlite_modern_cpp
std::experimental::optional is from @github/akrzemi1/Optional: https://github.com/akrzemi1/Optional

How to use (by examples):

Note that in the following examples, a table defined as follows is used:

		create table(
			id unsigned int auto_increment primary key,
			name varchar(50),
			weight double,
			birthday date,
			avatar int);
		);

		+----+--------------+--------+------------+--------+
		| id | name         | weight | birthday   | avatar |
		+----+--------------+--------+------------+--------+
		|  1 | Nguyen Van X |  62.54 | 1981-07-18 |      4 |
		|  2 | Tran Thi Y   |  56.78 | 1999-05-12 |      3 |
		|  3 | Bui Xuan Z   |   NULL | NULL       |      5 |
		+----+--------------+--------+------------+--------+

First, #include <mysql++11.h> whereever you want to use - Note that this is the ONLY step to do with your projects, nothing else!

Establishing a connection by constructor, or by connection::open() function:

	connection my("db4free.net", "kien", "kienkien", "kien");
	if (!my) {
		cout << "Connection failed" << endl;
		return;
	}

Example of simple query, without getting any value back (the returned object when not assigned is automatically destroyed):

	if (my.query("update person set avatar = floor(rand()*10)"))
		cout << "Successful" << endl;
	else cout << "Failed" << endl;

Simple query and simple way to get back a single value:

	auto row_count = my.query("select count(*) from person")
						.get_value<int>();
	cout << "Count: " << row_count << endl;

Queries can be passed using convenient printf-style, and optional type can be used to know whether the returned value is available:

	auto avg_weight = my.query("select avg(weight) from person where avatar >= %d or weight <= %f", 2, 70.5)
						.get_value<optional_type<double>>();
	if (avg_weight)
		cout << "Mean weight: " << *avg_weight << endl;
	else cout << "No mean weight value" << endl;

Example showing how to getting back multiple typed values in a row, optional type is also used to handle nullable values:

	int id;
	string name;
	optional_type<double> weight;

	auto res = my.query("select id, name, weight from person where id = %d", 3);
	if (!res.is_empty()) {
		res.fetch(id, name, weight);

		cout << "ID: " << id << ", name: " << name;
		if (weight) cout << ", weight: " << *weight;
		cout << endl;
	}

A multi-row data query using lambda function with row fields in parameter. Note that optional type can be used here as well, and datetime is a supporting type is used for handing date and time:

	my.query("select id, name, weight, birthday from person")
		.each([](int id, string name, optional_type<double> weight, optional_type<datetime> birthday) {
			// ...

			// return true to continue, false to stop
			return true;
		});

Another way to iterate through rows using a container-like object (note that unsuccessful/no-result queries will return an empty container):

	res = my.query("select id, name, weight from person");
	for (auto row : res.as_container<int, string, optional_type<double>>()) {
		tie(id, name, weight) = row;
		// ...
	}

or in C++98 style:

	res = my.query("select id, name, weight from person");
	auto ctn = res.as_container<int, string, optional_type<double>>();
	for (auto i = ctn.begin(); i != ctn.end(); i++) {
		tie(id, name, weight) = *i;
		// ...
	}

Of course, the-old-good-time-style loop is also possible:

	res = my.query("select id, name, weight from person");
	while (!res.eof()) {
		res.fetch(id, name, weight);
		// ...
		res.next();
	}

sambrg / mysql-cpp11