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//
// Copyright (c) 2022 Klemens Morgenstern (klemens.morgenstern@gmx.net)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#include <boost/sqlite.hpp>
#include <boost/describe/class.hpp>
#include <iostream>
using namespace boost;
// tag::query_t[]
struct users { std::string name; std::int64_t age; };
BOOST_DESCRIBE_STRUCT(users, (), (name, age));
// end::query_t[]
int main(int /*argc*/, char */*argv*/[])
{
system::error_code ec;
sqlite::error_info ei;
sqlite::connection conn;
#if defined(SQLITE_EXAMPLE_USE_DB)
// tag::conn_path[]
conn.connect("./my_db.db", SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, ec);
// end::conn_path[]
#else
// tag::conn_mem[]
conn.connect(sqlite::in_memory, SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, ec);
// end::conn_mem[]
#endif
if (ec)
goto error;
// tag::execute[]
conn.execute(R"(
CREATE TABLE IF NOT EXISTS users (
id INTEGER PRIMARY KEY AUTOINCREMENT,
name TEXT NOT NULL,
age INTEGER NOT NULL);
INSERT INTO users(name, age) VALUES('Alice', 30);
INSERT INTO users(name, age) VALUES('Bob', 25);
)", ec, ei);
// end::execute[]
if (ec)
goto error;
{
// tag::query1[]
sqlite::resultset q = conn.query("SELECT name, age FROM users ORDER BY id ASC;", ec, ei);
if (ec)
goto error;
// end::query1[]
// tag::query2[]
assert(q.current()[0].get_text() == "Alice");
assert(q.read_next(ec, ei)); // true if it's the last row!
if (ec)
goto error;
assert(q.current()[0].get_text() == "Bob");
// end::query2[]
}
// tag::query3[]
for (const auto & t :
conn.query<std::tuple<sqlite::string_view, std::int64_t>>("SELECT name, age FROM users;", ec, ei))
std::cout << "User " << std::get<0>(t) << " is " << std::get<1>(t) << " old." << std::endl;
if (ec)
goto error;
// end::query3[]
// tag::query4[]
for (const auto & a : conn.query<users>("SELECT age, name FROM users;", ec, ei))
std::cout << "User " << a.name << " is " << a.age << " old." << std::endl;
if (ec)
goto error;
// end::query4[]
// tag::query_strict[]
{
auto r = conn.query<users>("SELECT age, name FROM users;", ec, ei).strict();
while (r.read_next(ec, ei) && !ec)
{
// because this is strict, it takes ec & ei for conversion errors.
const auto & a = r.current(ec, ei);
if (ec)
break;
std::cout << "User " << a.name << " is " << a.age << " old." << std::endl;
}
}
if (ec)
goto error;
// end::query_strict[]
// tag::statement_insert[]
{
auto p = conn.prepare("insert into users (name, age) values (?1, ?2), (?3, ?4)", ec, ei);
if (!ec)
std::move(p).execute({"Paul", 31, "Mark", 51}, ec, ei);
if (ec)
goto error;
}
// end::statement_insert[]
// tag::statement_multi_insert[]
{
conn.execute("BEGIN TRANSACTION;", ec, ei);
if (ec)
goto error;
sqlite::transaction t{conn, sqlite::transaction::adopt_transaction}; // use a transaction to speed this up
auto st = conn.prepare(R"(insert into users ("name", age) values ($name, $age))", ec, ei);
if (!ec)
st.execute({{"name", "Allen"}, {"age", 43}}, ec, ei);
if (!ec)
st.execute({{"name", "Tom"}, {"age", 84}}, ec, ei);
if (!ec)
t.commit(ec, ei);
if (ec)
goto error;
}
// end::statement_multi_insert[]
// tag::to_upper[]
sqlite::create_scalar_function(
conn,
"to_upper",
[](sqlite::context<>, // <1>
boost::span<sqlite::value, 1u> val // <2>
) -> sqlite::result<std::string>
{
if (val[0].type() != sqlite::value_type::text)
return sqlite::error(SQLITE_MISUSE, "Value must be string"); // <2>
auto txt = val[0].get_text();
std::string res;
res.resize(txt.size());
std::transform(txt.begin(), txt.end(), res.begin(), [](char c){return std::toupper(c);});
return res;
},
sqlite::deterministic // <3>
, ec, ei);
if (ec)
goto error;
{
auto qu = conn.query("SELECT to_upper(name) FROM users WHERE name == 'Alice';", ec, ei);
if (ec) goto error;
assert(qu.current()[0].get_text() == "ALICE");
}
// end::to_upper[]
// tag::oldest[]
struct retirees
{
std::int64_t retirement_age;
std::int64_t count = 0u;
retirees(std::size_t retirement_age)
: retirement_age(retirement_age) {}
void step(span<sqlite::value, 1> args) noexcept // no possible errors, no result needed
{
if (args[0].get_int() >= retirement_age)
count += 1;
}
std::int64_t final() noexcept { return count; }
};
sqlite::create_aggregate_function<retirees>(conn, "retirees", std::make_tuple(65), {}, ec, ei);
if (ec) goto error;
{
auto q = conn.query("select retirees(age) from users;", ec, ei);
if (ec) goto error;
std::cout << "The amount of retirees is " << q.current()[0].get_text() << std::endl;
}
// end::oldest[]
return 0;
error:
fprintf(stderr, "sqlite failure: %s - %s\n", ec.message().c_str(), ei.message().c_str());
return EXIT_FAILURE;
}
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