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/****
Implemented example from here https://www.tutorialspoint.com/sqlite/sqlite_select_query.htm.
*/
#include <sqlite_orm/sqlite_orm.h>
#include <iostream>
using namespace sqlite_orm; using std::cout; using std::endl; using std::make_unique; using std::string;
void all_employees() { struct Employee { int id; std::string name; int age; std::unique_ptr<std::string> address; // optional
std::unique_ptr<double> salary; // optional
};
auto storage = make_storage("select.sqlite", make_table("COMPANY", make_column("ID", &Employee::id, primary_key()), make_column("NAME", &Employee::name), make_column("AGE", &Employee::age), make_column("ADDRESS", &Employee::address), make_column("SALARY", &Employee::salary))); storage.sync_schema(); storage.remove_all<Employee>(); // remove all old employees in case they exist in db..
// create employees..
Employee paul{-1, "Paul", 32, make_unique<string>("California"), make_unique<double>(20000.0)}; Employee allen{-1, "Allen", 25, make_unique<string>("Texas"), make_unique<double>(15000.0)}; Employee teddy{-1, "Teddy", 23, make_unique<string>("Norway"), make_unique<double>(20000.0)}; Employee mark{-1, "Mark", 25, make_unique<string>("Rich-Mond"), make_unique<double>(65000.0)}; Employee david{-1, "David", 27, make_unique<string>("Texas"), make_unique<double>(85000.0)}; Employee kim{-1, "Kim", 22, make_unique<string>("South-Hall"), make_unique<double>(45000.0)}; Employee james{-1, "James", 24, make_unique<string>("Houston"), make_unique<double>(10000.0)};
// insert employees. `insert` function returns id of inserted object..
paul.id = storage.insert(paul); allen.id = storage.insert(allen); teddy.id = storage.insert(teddy); mark.id = storage.insert(mark); david.id = storage.insert(david); kim.id = storage.insert(kim); james.id = storage.insert(james);
// print users..
cout << "paul = " << storage.dump(paul) << endl; cout << "allen = " << storage.dump(allen) << endl; cout << "teddy = " << storage.dump(teddy) << endl; cout << "mark = " << storage.dump(mark) << endl; cout << "david = " << storage.dump(david) << endl; cout << "kim = " << storage.dump(kim) << endl; cout << "james = " << storage.dump(james) << endl;
// select all employees..
auto allEmployees = storage.get_all<Employee>();
cout << "allEmployees[0] = " << storage.dump(allEmployees[0]) << endl; cout << "allEmployees count = " << allEmployees.size() << endl;
// now let's select id, name and salary..
auto idsNamesSalarys = storage.select(columns(&Employee::id, &Employee::name, &Employee::salary)); for(auto& row: idsNamesSalarys) { // row's type is tuple<int, string, unique_ptr<double>>
cout << "id = " << get<0>(row) << ", name = " << get<1>(row) << ", salary = "; if(get<2>(row)) { cout << *get<2>(row); } else { cout << "null"; } cout << endl; }
cout << endl;
auto allEmployeeTuples = storage.select(asterisk<Employee>()); cout << "allEmployeeTuples count = " << allEmployeeTuples.size() << endl; for(auto& row: allEmployeeTuples) { // row's type is std::tuple<int, string, int, std::unique_ptr<string>,
// std::unique_ptr<double>>
cout << get<0>(row) << '\t' << get<1>(row) << '\t' << get<2>(row) << '\t'; if(auto& value = get<3>(row)) { cout << *value; } else { cout << "null"; } cout << '\t'; if(auto& value = get<4>(row)) { cout << *value; } else { cout << "null"; } cout << '\t' << endl; }
cout << endl;
auto allEmployeeObjects = storage.select(object<Employee>()); cout << "allEmployeeObjects count = " << allEmployeeObjects.size() << endl; for(auto& employee: allEmployeeObjects) { cout << employee.id << '\t' << employee.name << '\t' << employee.age << '\t'; if(auto& value = employee.address) { cout << *value; } else { cout << "null"; } cout << '\t'; if(auto& value = employee.salary) { cout << *value; } else { cout << "null"; } cout << '\t' << endl; }
cout << endl; }
void all_artists() { struct Artist { int id; std::string name; };
struct Album { int id; int artist_id; };
auto storage = make_storage("", make_table("artists", make_column("id", &Artist::id, primary_key().autoincrement()), make_column("name", &Artist::name)), make_table("albums", make_column("id", &Album::id, primary_key().autoincrement()), make_column("artist_id", &Album::artist_id), foreign_key(&Album::artist_id).references(&Artist::id))); storage.sync_schema(); storage.transaction([&storage] { auto artistPk = storage.insert(Artist{-1, "Artist"}); storage.insert(Album{-1, artistPk}); storage.insert(Album{-1, artistPk}); return true; });
// SELECT artists.*, albums.* FROM artists JOIN albums ON albums.artist_id = artist.id
cout << "artists.*, albums.*\n"; // row's type is std::tuple<int, std::string, id, int>
for(auto& row: storage.select(columns(asterisk<Artist>(), asterisk<Album>()), join<Album>(on(c(&Album::artist_id) == &Artist::id)))) { cout << get<0>(row) << '\t' << get<1>(row) << '\t' << get<2>(row) << '\t' << get<3>(row) << '\n'; } cout << endl; }
int main() {
try { all_employees(); all_artists(); } catch(const std::system_error& e) { cout << "[" << e.code() << "] " << e.what(); }
return 0; }
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