ORM for C++: Comparison and Code Examples

ORM for C++: Comparison and Usage Examples

In modern C++ development, working with databases often requires a balance between performance and convenience. Unlike languages with a rich ORM ecosystem (such as Python or Java), C++ offers a narrower but mature selection of tools. In this article, we will compare four popular libraries: ODB, SQLiteCpp, Soci, and sqlpp11. We will examine their architecture, syntax, performance, and code examples.

1. ODB — The Industry Standard

ODB is a full-featured ORM compiler for C++. It generates code from header files, supports relational databases (MySQL, PostgreSQL, SQLite, Oracle), and provides powerful object-relational mapping.

Key Features:

Automatic code generation via a precompiler (odb)
Support for inheritance, polymorphism, and STL containers
Lazy loading, caching, transactions

Example: Model and Query

// person.hxx#pragma once#include <string>#include <odb/core.hxx>

#pragma db objectclass Person {public:    Person() = default;    Person(const std::string& name, int age)        : name_(name), age_(age) {}

    const std::string& name() const { return name_; }    int age() const { return age_; }

private:    friend class odb::access;    #pragma db id auto    unsigned long id_;    std::string name_;    int age_;};

// main.cpp#include <odb/database.hxx>#include <odb/sqlite/database.hxx>#include "person.hxx"#include "person-odb.hxx"

int main() {    auto db = std::make_shared<odb::sqlite::database>("test.db");        // Insert    Person p("Alice", 30);    db->persist(p);        // Query    using query = odb::query<Person>;    auto result = db->query<Person>(query::age > 25);    for (const auto& person : result) {        std::cout << person.name() << "";    }    return 0;}

2. SQLiteCpp — Lightweight Wrapper

SQLiteCpp is a minimalist C++ wrapper over the SQLite C API. It is not a full ORM, but it provides a convenient RAII interface for working with SQL queries.

Key Features:

Dependency only on SQLite3
Simple API: Database, Statement, Transaction
Support for prepared statements and parameter binding

Example: Insert and Select

#include <SQLiteCpp/Database.h>#include <iostream>

int main() {    SQLite::Database db("test.db", SQLite::OPEN_READWRITE | SQLite::OPEN_CREATE);        // Create table    db.exec("CREATE TABLE IF NOT EXISTS person (id INTEGER PRIMARY KEY, name TEXT, age INT)");        // Insert with parameters    SQLite::Statement insert(db, "INSERT INTO person (name, age) VALUES (?, ?)");    insert.bind(1, "Bob");    insert.bind(2, 25);    insert.exec();        // Select    SQLite::Statement query(db, "SELECT name, age FROM person WHERE age > ?");    query.bind(1, 20);    while (query.executeStep()) {        std::cout << query.getColumn(0).getText()                   << " - " << query.getColumn(1).getInt() << "";    }    return 0;}

3. Soci — Universal Database Access

Soci is a library for working with various databases (MySQL, PostgreSQL, SQLite, Oracle) through a unified interface. It provides both dynamic queries and support for ORM-like mapping.

Key Features:

Support for multiple backends via plugins
Parameter binding using the << operator and into()
Support for transactions and bulk operations

Example: Working with Queries


                
    
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