#include <fstream>
#include <iostream>
#include <vector>

using namespace std;

class db_engine {
	vector<string> cmdList;
	//vector<vector<string>> table;

public:
	db_engine();
	void createCmd(string tableName, vector<string> attributes, vector<string> pkeys);
	//void openCmd();
	void saveCmd();
	void showCmd(string tableName);
	void insertQuery(string tableName, vector<string> t);
	void deleteQuery();
	void selectQuery();
	void projectQuery();
	void productQuery();
	bool unionComp();
};