condition support & selection

Attribute.cpp

@@ -60,4 +60,8 @@ void Attribute::display(){
 	}
 	
 	cout << "-------------\n";
+}
+
+void Attribute::clearAllValues(){
+	values.clear();
 }

Attribute.h

@@ -1,3 +1,4 @@
+#pragma once
 #include <iostream>
 #include <vector>
 
@@ -22,4 +23,5 @@ public:
 	bool isKey();
 	int getSize();
 	void display();
+	void clearAllValues();
 };

Condition.cpp

@@ -1,29 +1,58 @@
 #include <iostream>
-#include "Attribute.h"
+#include "Relation.h"
 
 using namespace std;
 
 //currently only implementing for comparison
-void equality(Attribute a, string s){
-	
+Relation equality(string attName, string s, Relation r){
+	Attribute att = r.getAttributeByName(attName);
+	vector<Attribute> r_atts = r.getAttributes();
+	vector<Attribute> new_atts = r_atts;
+
+	for (int i = 0; i < new_atts.size(); ++i) {
+		new_atts[i].clearAllValues();
+	}	
+
+	for (int i = 0; i < att.getSize(); ++i) {
+		if (att[i] == s){
+			for (int j = 0; j < r_atts.size(); ++j){
+				new_atts[j].addCell(r_atts[j][i]);
+			}
+		}
+	}
+
+	//currently all returned relations are called TEMP
+	Relation new_r("TEMP", new_atts);
+	return new_r;
+}
+/*
+vector<Attribute> equality(Attribute a, int i){
+	for (int i = 0; i < a.getSize(); ++i) {
+		//
+	}	
 }
 
-void equality(Attribute a, int i){
-	
+vector<Attribute> gt(Attribute a, int i){
+	for (int i = 0; i < a.getSize(); ++i) {
+		//
+	}	
 }
 
-void gt(Attribute a, int i){
-	
+vector<Attribute> lt(Attribute a, int i){
+	for (int i = 0; i < a.getSize(); ++i) {
+		//
+	}	
 }
 
-void lt(Attribute a, int i){
-	
+vector<Attribute> gte(Attribute a, int i){
+	for (int i = 0; i < a.getSize(); ++i) {
+		//
+	}	
 }
 
-void gte(Attribute a, int i){
-	
+vector<Attribute> lte(Attribute a, int i){
+	for (int i = 0; i < a.getSize(); ++i) {
+		//
+	}	
 }
-
-void lte(Attribute a, int i){
-	
-}
+*/

Condition.h

@@ -1,13 +1,4 @@
-#include <iostream>
-#include "Attribute.h"
+#pragma once
+#include "Relation.h"
 
-using namespace std;
-
-class Condition{
-	Attribute att;
-	
-public:
-	//currently only implemented for comparison
-	Condition(Attribute a);
-	Condition(Attribute a);
-};
+Relation equality(string attName, string s, Relation r);

DBEngine.cpp

@@ -1,6 +1,7 @@
 #include <fstream>
 #include <iostream>
 #include <vector>
+#include "Condition.h"
 #include "DBEngine.h"
 
 DBEngine::DBEngine(){
@@ -48,6 +49,11 @@ void DBEngine::saveToFile(vector<string> cmds){
 	file.close();
 }
 
+
+Relation DBEngine::selection(string attName, string s, Relation r){
+	equality(attName, s, r);
+}
+
 //assumes that all attribute titles are unique
 Relation DBEngine::projection(vector<string> input, Relation r){
 	
@@ -78,3 +84,13 @@ void DBEngine::rename(Relation& r, vector<string> oldnames, vector<string> newna
 	}
 }
 
+Relation DBEngine::setUnion(Relation r1, Relation r2){
+	if (r1.getAttributes() != r2.getAttributes()){
+		cout << "Failure to union: the relations are not union-compatible";
+		return;
+	}
+
+	else {
+
+	}
+}

DBEngine.h

@@ -1,3 +1,4 @@
+#pragma once
 #include <fstream>
 #include <iostream>
 #include <vector>
@@ -17,10 +18,10 @@ public:
 	//void showTable(Relation r);
 	Relation& getTableFromName(string n);
 	void saveToFile(vector<string> cmds);
-	//Relation selection();
+	Relation selection(string attName, string s, Relation r);
 	Relation projection(vector<string> input, Relation r);
 	void rename(Relation& r, vector<string> oldnames, vector<string> newnames);
-	//void setUnion();
+	Relation setUnion();
 	//void setDiff();
-	//void crossProduct();
+	//void crossProduct();
 };

Relation.cpp

@@ -17,6 +17,10 @@ string Relation::getTableName(){
 	return name; 
 }
 
+Attribute Relation::operator[](int i){ 
+	return att[i]; 
+}
+
 vector<Attribute> Relation::getAttributes(){ 
 	return att; 
 }

Relation.h

@@ -1,3 +1,4 @@
+#pragma once
 #include <iostream>
 #include <vector>
 #include "Attribute.h"
@@ -11,6 +12,7 @@ public:
 	Relation(string n);
 	Relation(string n, vector<Attribute> a);
 	string getTableName();
+	Attribute operator[](int i);
 	vector<Attribute> getAttributes();
 	vector<string> getAttributeNames();
 	Attribute& getAttributeByName(string s);

test.cpp

@@ -1,5 +1,6 @@
 #include <iostream>
 #include <vector>
+#include "Condition.h"
 #include "DBEngine.h"
 
 using namespace std;
@@ -26,31 +27,8 @@ int main() {
 	v.push_back(att2);
 	v.push_back(att3);
 	
-	//Relation r("Food", v);
-	//r.renameAttribute("Breakfast", "BFST");
-	//r.display();
-	
 	engine.createTable("Food", v);
-	
-	vector<string> tuple;
-	tuple.push_back("Omelette");
-	tuple.push_back("Fried Rice");
-	tuple.push_back("Grouper");
-	
-	engine.getTableFromName("Food").insertTuple(tuple);
-	
-	vector<string> old;
-	vector<string> newa;
-	
-	old.push_back("Breakfast");
-	old.push_back("Lunch");
-	old.push_back("Dinner");
-	
-	newa.push_back("Tsafkaerb");
-	newa.push_back("Hcnul");
-	newa.push_back("Rennid");
-	
-	engine.rename(engine.getTableFromName("Food"), old, newa);
-	engine.getTableFromName("Food").display();
-	cout << "finished";
+
+	Relation r = equality("Breakfast", "Pancakes", engine.getTableFromName("Food"));
+	r.display();
 }