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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);
R.add_scheme(scheme);
}
}
return R;
}
Relation Relation::select(int pos1, int pos2) {
Relation R;
for (auto tuple : tuples ) {
if(tuple[pos1] == tuple[pos2] ){
R.add_tuple(tuple);
}
}
R.add_scheme(scheme);
return R;
}
string Relation::project(vector<string> name, vector<int> pos) {
stringstream ss;
//if(!tuples.empty())
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;
}
Scheme Relation::get_scheme() {
return scheme;
}
Relation Relation::join(Relation R1, Relation R2) {
Scheme S1 = R1.get_scheme();
Scheme S2 = R2.get_scheme();
vector<int> pos = get_no_join_pos(S1,S2);
Scheme SC = join_scheme(S1, S2);
Relation R;
R.add_scheme(SC);
set<Tuple> TS1 = R1.get_tuples();
set<Tuple> TS2 = R2.get_tuples();
for (auto tuple1 : TS1) {
for (auto tuple2 : TS2) {
if ((can_join(tuple1, tuple2, S1, S2) == true)) {
Tuple t = R.join_tuple(tuple1, tuple2, pos);
R.add_tuple(t);
}
}
}
/*make the scheme s for the result relation
(combine r1's scheme with r2's scheme)
make a new empty relation r using scheme s
for each tuple t1 in r1
for each tuple t2 in r2
if t1 and t2 can join
join t1 and t2 to make tuple t
add tuple t to relation r
end if
end for
end for*/
return R;
}
Relation Relation::rule_project(vector<int> pos, Relation R) {
Relation rtemp;
for (auto tuple : R.get_tuples()) {
Tuple ttemp;
for (unsigned int i = 0; i < pos.size(); i++) {
ttemp.push_back(tuple[pos[i]]);
}
rtemp.add_tuple(ttemp);
}
rtemp.add_scheme(scheme);
return rtemp;
}
Scheme Relation::join_scheme(Scheme S1, Scheme S2) {
Scheme tempSC;
for (unsigned int i = 0; i < S1.size(); i++) {
for (unsigned int y = 0; y < S2.size(); y++) {
if (S1[i] == S2[y]) {
S2.erase(remove(S2.begin(), S2.end(), S1[i]));
}
}
tempSC.push_back(S1[i]);
}
for (auto scheme : S2) {
tempSC.push_back(scheme);
}
return tempSC;
}
vector<int> Relation::get_no_join_pos(Scheme S1, Scheme S2) {
vector<int> pos;
for (unsigned int i = 0; i < S1.size(); i++) {
for (unsigned int y = 0; y < S2.size(); y++) {
if (S1[i] == S2[y]) {
pos.push_back(y);
}
}
}
return pos;
}
bool Relation::can_join(Tuple T1, Tuple T2, Scheme S1, Scheme S2) {
bool bvalue = true;
for (unsigned int i = 0; i < S1.size(); i++) {
string value1 = T1[i];
string name1 = S1[i];
for (unsigned int y = 0; y < S2.size(); y++) {
string value2 = T2[y];
string name2 = S2[y];
if ((name1 == name2) && (value1 != value2)) {
bvalue = false;
}
}
}
/*
value1 in tuple1
foreach name1 in scheme2
value2 in tupe2
foreach name2 in scheme2
if(name1 == name2 && value1 != value2)
return false (not joinable)
}
return true (joinable)
*/
return bvalue;
}
Tuple Relation::join_tuple(Tuple T1, Tuple T2, vector<int> pos) {
Tuple tupleTemp;
for (auto param : T1) {
tupleTemp.push_back(param);
}
for (unsigned int i = 0; i < T2.size(); i++) {
unsigned int count = 0;
for (unsigned spot : pos) {
if (spot != i) {
count++;
}
}
if (count == pos.size()) {
tupleTemp.push_back(T2[i]);
}
//T2.erase(remove(T2.begin(), T2.end(), T2[spot]));
}
return tupleTemp;
}
Relation Relation::unioning(Relation R1, Relation R2) {
set<Tuple> tupleset1 = R1.get_tuples();
set<Tuple> tupleset2 = R2.get_tuples();
for (auto tuple : tupleset2) {
R1.add_tuple(tuple);
}
return R1;
}