MyDB.cpp

class MyDB {
private:
  sqlite3* db;
  bool conn;
public:
  MyDB():db(nullptr), conn(false){}
  ~MyDB() {
    if(conn) {
      sqlite3_close(db);
    }
  }
  bool connect(const std::string& db_name) {
    if(conn) return false;
    int rc = sqlite3_open(db_name.c_str(), &db);
    if(rc) {
      fprintf(stderr, "Can't open database : %s\n", sqlite3_errmsg(db));
      return conn = false;
    }
    return conn = true;
  }
  void close() {
    if(conn) {
      sqlite3_close(db);
    }
  }
  bool exec(const std::string& sql,
	    int (*callback)(void* data, int argc, char** argv, char** azColName)) {
    char* zErrMsg = NULL;
    const char* data = "Callback function called!";
    int rc = sqlite3_exec(db, sql.c_str(), callback, (void*)data, &zErrMsg);
    if(rc != SQLITE_OK) {
      fprintf(stderr, "SQL error: %s\n", zErrMsg);
      sqlite3_free(zErrMsg);
      return false;
    }
    return true;
  }
};