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Relation.cpp
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Relation.cpp
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//
// Relation.cpp
// Project2
//
// Created by Michael Bird on 7/21/14.
// Copyright (c) 2014 Michael Bird. All rights reserved.
//
#include "Relation.h"
Relation::Relation() {}
Relation::~Relation() {}
void Relation::add_tuple(vector<Tuple> tuple) {
for(auto tuple_item : tuple) {
tuples.insert(tuple_item);
}
}
void Relation::add_tuple(Tuple tuple) {
tuples.insert(tuple);
}
void Relation::add_scheme(Scheme scheme_in) {
scheme = scheme_in;
}
Relation Relation::select(int pos, string value) {
Relation R;
for (auto tuple : tuples ) {
if(tuple[pos] == value ){
R.add_tuple(tuple);
}
}
return R;
}
Relation Relation::select(int pos1, int pos2) {
Relation R;
for (auto tuple : tuples ) {
if(tuple[pos1] == tuple[pos2] ){
R.add_tuple(tuple);
}
}
return R;
}
string Relation::project(vector<string> name, vector<int> pos) {
stringstream ss;
for (auto tuple : tuples) {
for (unsigned int i = 0; i < name.size(); i++) {
if(i == 0)
ss << " "<<name[i] << "=" << tuple[pos[i]];
else
ss << ", "<<name[i] << "=" << tuple[pos[i]];
}
ss << "\n";
}
return ss.str();
}
set<Tuple> Relation::get_tuples() {
return tuples;
}