Squashed 'subprojects/boost-sqlite/' content from commit 3378e35

git-subtree-dir: subprojects/boost-sqlite
git-subtree-split: 3378e353705271e569cf4ba15c467b840a39798c

1 files changed, 197 insertions, 0 deletions

diff --git a/example/tutorial_ec.cpp b/example/tutorial_ec.cpp
new file mode 100644
index 0000000..2c6af7f
--- /dev/null
+++ b/example/tutorial_ec.cpp
@@ -0,0 +1,197 @@
+//
+// 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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