//---------------------------------------------------------------------------
static void readIndex(istream& in,map<Register,unsigned>& index,Attribute::Type type,unsigned cardinality)
// Read an index
{
unsigned count;
in.read(reinterpret_cast<char*>(&count),sizeof(count));
if (count!=cardinality) {
cerr << "index corruption encountered, reload the database" << endl;
throw;
}
index.clear();
switch (type) {
case Attribute::Type::Int:
for (unsigned index2=0;index2<count;++index2) {
int val; unsigned pos;
in.read(reinterpret_cast<char*>(&val),sizeof(val)); in.read(reinterpret_cast<char*>(&pos),sizeof(pos));
Register r; r.setInt(val);
index[r]=pos;
}
break;
case Attribute::Type::Double:
for (unsigned index2=0;index2<count;++index2) {
double val; unsigned pos;
in.read(reinterpret_cast<char*>(&val),sizeof(val)); in.read(reinterpret_cast<char*>(&pos),sizeof(pos));
Register r; r.setDouble(val);
index[r]=pos;
}
break;
case Attribute::Type::Bool:
for (unsigned index2=0;index2<count;++index2) {
bool val; unsigned pos;
in.read(reinterpret_cast<char*>(&val),sizeof(val)); in.read(reinterpret_cast<char*>(&pos),sizeof(pos));
Register r; r.setBool(val);
index[r]=pos;
}
break;
case Attribute::Type::String:
for (unsigned index2=0;index2<count;++index2) {
unsigned valLen,pos; string val;
in.read(reinterpret_cast<char*>(&valLen),sizeof(valLen));
val.resize(valLen);
in.read(const_cast<char*>(val.data()),valLen);
in.read(reinterpret_cast<char*>(&pos),sizeof(pos));
Register r; r.setString(val);
index[r]=pos;
}
break;
}
}
//executes query canonically
void Executor::execute(query q){
Database db;
db.open("data/uni");
if(q.from.size() >= 1){
unordered_map<string, unordered_map<string, const Register*>> registers;
unique_ptr<Operator> crossproduct(nullptr);
//Make crossproducts
int counter = 0;
for(auto it = q.from.begin(); it != q.from.end(); ++it) {
unique_ptr<Tablescan> tablescan(new Tablescan(db.getTable(it->first)));
//Used for constants push down
//Get names of all attributes an populate tables
vector<string> names = db.getTable(it->first).getAttributeNames();
populateRegisterTable(®isters, *tablescan, &names, it->second);
unique_ptr<Operator> selection(move(tablescan));
//Find pushdowns and execute them
for(auto it2 = q.where.begin(); it2 != q.where.end(); it2++){
if((*it2).r_attr.first == "" && (*it2).l_attr.first == it->second){ //See if bindings are the same
Register* registertmp = new Register(); //tmpp
int attrIndex = db.getTable(it->first).findAttribute((*it2).l_attr.second);
if(attrIndex < 0){
throw "NO EXISTENT ATTRIBUTE";
}
const Attribute& attr = db.getTable(it->first).getAttribute(attrIndex);
Attribute::Type attr_type = attr.getType();
string name = attr.getName();
//Check type for attribute
if(attr_type == Attribute::Type::Int)
{
int tmp;
size_t end;
tmp = stoi((*it2).r_attr.second, &end);
registertmp->setInt(tmp);
}
else if(attr_type == Attribute::Type::Double)
{
int tmp;
size_t end;
tmp = stod((*it2).r_attr.second, &end);
registertmp->setInt(tmp);
}
else if(attr_type == Attribute::Type::Bool)
{
//TODO
}
else
{
registertmp->setString((*it2).r_attr.second);
}
unique_ptr<Operator> seltmp(new Selection(move(selection), registers[it->second][(*it2).l_attr.second] ,registertmp )); //tmp
selection.swap(seltmp);
}
}
if(crossproduct == nullptr){
crossproduct.swap(selection);
}
else{
unique_ptr<Operator> dummy(new CrossProduct(move(selection), move(crossproduct)));
crossproduct.swap(dummy);
}
}
//Find join conditions and execute them
for(auto it2 = q.where.begin(); it2 != q.where.end(); it2++){
if((*it2).r_attr.first != ""){ //See if bindings are the
string rightTable;
string leftTable;
for(auto it3 = q.from.begin(); it3 != q.from.end(); ++it3 ){
if(it3->second == (*it2).r_attr.first) {
rightTable = it3->second;
}
else if(it3->second == (*it2).l_attr.first) {
leftTable = it3->second;
}
}
unique_ptr<Operator> seltmp(new Selection(move(crossproduct), registers[leftTable][(*it2).l_attr.second] ,registers[rightTable][(*it2).r_attr.second] )); //tmp
crossproduct.swap(seltmp);
}
}
//Print the names of the students
Printer out(move(crossproduct));
out.open();
while (out.next());
out.close();
}
}