Supported platforms

Supported databases

Namespace

High level API

Simple one record example

#include<Lightweight/Lightweight.hpp>// Define a person structure, mapping to a table from the databasestructPerson{    Field<SqlGuid, PrimaryKey::AutoAssign> id;    Field<SqlAnsiString<25>> name;    Field<bool> is_active {true };    Field<std::optional<int>> age;};voidCRUD(DataMapper& dm){// Creates the table if it does not exist    dm.CreateTable<Person>();// Create a new person and create a database entryauto person = Person {.name ="John Doe", .is_active =true, .age =24};    dm.Create(person);// Update the age and save to the database    person.age =25;    dm.Update(person);// Query the person by primary keyif (autoconst po = dm.Query<Person>(person.id); po)std::println("Person: {} ({})", po->name,DataMapper::Inspect(*po));// Query all persons    std::vector<Person>const persons = dm.Query<Person>().All();// Query all persons with some filter and order by nameautoconst records = dm.Query<Person>()                             .Where(FieldNameOf<&Person::is_active>,"=",true)                             .OrderBy(FieldNameOf<&Person::name>)                             .All();// Delete the person    dm.Delete(person);}

Foreign keys relation

structUser{    Light::Field<Light::SqlGuid, Light::PrimaryKey::AutoAssign, SqlRealName {"user_id" }> id {};    Light::Field<Light::SqlAnsiString<30>> name {};};structEmail{    Light::Field<Light::SqlGuid, Light::PrimaryKey::AutoAssign> id {};    Light::Field<Light::SqlAnsiString<30>> address {};    Light::BelongsTo<&User::id, Light::SqlRealName {"user_id" }> user {};};

auto dm = Light::DataMapper::Create();auto email = dm->QuerySingle<Email>(some_email_id).value_or(Email{});auto user_name = email.user->name;// lazily loads the user record

Mapping query results to a simple struct

#include<Lightweight/Lightweight.hpp>structSimpleStruct{uint64_t pkFromA;uint64_t pkFromB;    SqlAnsiString<30> c1FromA;    SqlAnsiString<30> c2FromA;    SqlAnsiString<30> c1FromB;    SqlAnsiString<30> c2FromB;};voidSimpleStructExample(DataMapper& dm){if (auto maybeObject = dm.Query<SimpleString>("SELECT A.pk, B.pk, A.c1, A.c2, B.c1, B.c2 FROM A LEFT JOIN B ON A.pk = B.pk"); maybeObject)    ))    {for (autoconst& obj : *maybeObject)std::println("{}",DataMapper::Inspect(obj));    }}

Mapping query to multiple struct

structCustomBindingA{    Field<uint64_t, PrimaryKey::ServerSideAutoIncrement> id {};    Field<int> number {};    Field<SqlAnsiString<20>> name {};    Field<SqlDynamicWideString<1000>> description {};};structCustomBindingB{    Field<uint64_t, PrimaryKey::ServerSideAutoIncrement> id {};    Field<SqlAnsiString<20>> title {};    Field<SqlDateTime> date_time {};    Field<uint64_t> a_id {};    Field<uint64_t> c_id {};};structCustomBindingC{    Field<uint64_t, PrimaryKey::ServerSideAutoIncrement> id {};    Field<double> value {};    Field<SqlAnsiString<20>> comment {};};

auto dm = Light::DataMapper::Create();auto query = dm->FromTable(RecordTableName<CustomBindingA>)                 .Select()                 .Fields<CustomBindingA, CustomBindingB>()                 .Field(QualifiedColumnName<"C.id">)                 .Field(QualifiedColumnName<"C.comment">)                 .InnerJoin<&CustomBindingB::a_id, &CustomBindingA::id>()                 .InnerJoin<&CustomBindingC::id, &CustomBindingB::c_id>()                 .OrderBy(QualifiedColumnName<"A.id">)                 .All();

SELECT"A"."id","A"."number","A"."name","A"."description","B"."id","B"."title","B"."date_time","B"."a_id","B"."c_id",""C"."id"","C"."comment"FROM"A"INNER JOIN"B"ON"B"."a_id"="A"."id"INNER JOIN"C"ON"C"."id"="B"."c_id"ORDER BY"A"."id"ASC

structPartOfC{uint64_t id {};    SqlAnsiString<20> comment {};};autoconst records = dm->Query<CustomBindingA, CustomBindingB, PartOfC>(query);for (autoconst& [a, b, c]: records){// ...}

Using SQLite for testing on Windows operating system

SQLite ODBC driver installation on other operating systems

# Fedora Linuxsudo dnf install sqliteodbc# Ubuntu Linuxsudo apt install sqliteodbc# macOSarch -arm64 brew install sqliteodbc

Generate example for the existing database

cmake --build build --target ddl2cpp

 ./build/src/tools/ddl2cpp --connection-string"DRIVER=SQLite3;Database=test.db" --make-aliases --naming-convention CamelCase  --output ./src/examples/example.hpp --generate-example

ConnectionString:'DSN=YourDSN;UID=YourUser;PWD=YourSecret'OutputDirectory:'src/entities'MakeAliases:trueNamingConvention:CamelCase

cmake --preset linux-clang-debug -DLIGHWEIGHT_EXAMPLE=ON -B build

cmake --build build&& ./build/src/examples/example

Compile using C++26 reflection support

docker buildx build --progress=plain -f .github/DockerReflection --load.