SQLon

A lightweight, type-safe, database-agnostic SQL query builder for C++17.

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Overview

SQLon is a lightweight, database-agnostic SQL query builder. It represents queries as a runtime AST, renders SQL for PostgreSQL, MySQL, SQLite, Oracle, SQL Server, or Firebird, and returns owned parameter values in binding order.

SQLon is not an ORM and does not connect to a database. Applications keep control over their SQL and database client while gaining composable queries, type-checked expressions, and safe parameters.

SQLon is inspired by Qrafter and adapts its explicit, type-safe query-building approach to modern C++.

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Usage

#include <sqlon/sqlon.h>

#include <cstdint>
#include <iostream>
#include <string>

struct UsersTable final : sqlon::table {
  using sqlon::table::table;

  sqlon::column<std::int64_t> id{*this, "id"};
  sqlon::column<std::string> name{*this, "name"};
  sqlon::column<bool> active{*this, "active"};
};

int main()
{
  const UsersTable users{"users"};

  sqlon::conditions where;
  where.add(users.active.eq(true));
  where.add(users.name.eq("Alice"));

  const auto query = sqlon::select(users.id, users.name).from(users).where(where);
  const auto result = sqlon::render(query, sqlon::presets::postgresql());
  std::cout << result.sql << '\n';
  std::cout << "parameters: " << result.parameters.size() << '\n';
}

result.sql contains the rendered statement and result.parameters contains the values to pass to a database client. SQLon also supports mutations, joins, subqueries, CTEs, set operations, window functions, and reusable prepared-query definitions.

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Build

SQLon requires C++17 and CMake 3.13 or newer.

cmake -S . -B build -DCMAKE_BUILD_TYPE=Release -DSQLON_BUILD_TESTS=ON
cmake --build build --parallel
ctest --test-dir build --output-on-failure

Tests and examples are opt-in through SQLON_BUILD_TESTS and SQLON_BUILD_EXAMPLES. Static libraries are built by default; pass -DBUILD_SHARED_LIBS=ON to build a shared library.

Developer presets use the <compiler>-<configuration>-<linkage> naming scheme. For example:

cmake --preset clang-relwithdebinfo-shared
cmake --build --preset clang-relwithdebinfo-shared --parallel
ctest --preset clang-relwithdebinfo-shared

GCC and Clang presets cover Debug, Release, and RelWithDebInfo builds for static and shared libraries. Visual Studio is a multi-configuration generator, so its configure presets select linkage, such as msvc-shared; matching build and test presets include the configuration, such as msvc-debug-shared. Run cmake --list-presets to see the presets available on the current platform.

Installed consumers can link the sqlon::sqlon CMake target. CPack can produce TGZ and ZIP archives on every supported platform, plus DEB and RPM packages on Linux.

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License

SQLon is available under the MIT License.