void deleteFromTable(string tableName, string whereCondition) {
if(whereCondition.empty()){
if(!schemaManager.relationExists(tableName)) {
cout<<"Illegal Table Name"<<endl;
return;
}
Relation *relation = schemaManager.getRelation(tableName);
while(relation->getNumOfBlocks())
relation->deleteBlocks(relation->getNumOfBlocks()-1);
}
else {
Relation *relation = schemaManager.getRelation(tableName);
for(int i=0;i<relation->getNumOfBlocks();i++) {
relation->getBlock(i,0);
Block *block = mainMemory.getBlock(0);
vector<Tuple> tuples = block->getTuples();
for(int j=0;j<tuples.size();j++) {
if(!tuples[j].isNull() && whereConditionEvaluator(whereCondition, tuples[j])) {
block->nullTuple(j);
}
}
relation->setBlock(i,0);
}
}
}
void insertTuple(string tableName, Tuple tuple) {
Relation *relation = schemaManager.getRelation(tableName);
if(relation->getNumOfBlocks()>0){
relation->getBlock(relation->getNumOfBlocks()-1,9);
Block *block = mainMemory.getBlock(9);
if(block->isFull()){
block->clear();
block->appendTuple(tuple);
relation->setBlock(relation->getNumOfBlocks(),9);
}
else {
block->appendTuple(tuple);
relation->setBlock(relation->getNumOfBlocks()-1,9);
}
}
else {
Block *block = mainMemory.getBlock(9);
block->clear();
block->setTuple(0,tuple);
relation->setBlock(0,9);
}
}
string distinct(string tableName) {
Relation *relation = schemaManager.getRelation(tableName);
Schema schema = relation->getSchema();
int size = relation->getNumOfBlocks();
vector<Tuple> tuples;
bool flag = true;
//one-pass
if(size<=10) {
relation->getBlocks(0,0,size);
tuples = mainMemory.getTuples(0,size);
tuples = getDistinctTuples(tuples);
Relation *relation1 = schemaManager.createRelation(tableName+"_distinct",schema);
insertTuples(tableName+"_distinct",tuples);
}
//two pass
else {
int index = 0, loadSize=10;
while(size>0) {
relation->getBlocks(index,0,loadSize);
for(int i=0;i<loadSize;i++) {
Block *block = mainMemory.getBlock(i);
for(int j=0;j<block->getNumTuples();j++) {
tuples.push_back(block->getTuple(j));
}
}
tuples = getDistinctTuples(tuples);
//partition(tuples, 0, tuples.size()-1);
if(flag) {
Relation *relation2= schemaManager.createRelation(tableName+"_dis", schema);
flag = false;
}
insertTuples(tableName+"_dis", tuples);
Relation *relation2 = schemaManager.getRelation(tableName+"_dis");
tuples.clear();
index = index+10;
size = size-10;
if(size<10)
loadSize = size;
}
if(size<=100) {
Relation *relation2 = schemaManager.createRelation(tableName+"_distinct", schema);
relation = schemaManager.getRelation(tableName+"_dis");
int buckets = relation->getNumOfBlocks()/10;
vector<Tuple> tuples;
for(int i=0;i<10;i++) {
for(int j=0;j<buckets;j++) {
if(j*10+i > relation->getNumOfBlocks()) break;
relation->getBlock(i+10*j,j);
Block *block = mainMemory.getBlock(j);
for(int k=0;k<block->getNumTuples();k++) {
tuples.push_back(block->getTuple(k));
}
}
}
tuples = getDistinctTuples(tuples);
insertTuples(tableName+"_distinct", tuples);
tuples.clear();
schemaManager.deleteRelation(tableName+"_dis");
}
else
cerr<<"Table size exceeds the limit size(mainMemory)^2"<<endl;
}
return tableName+"_distinct";
}
string projection(vector<string> attributes, string tableName, string whereCondition) {
Relation *relation = schemaManager.getRelation(tableName);
Schema tableSchema = relation->getSchema();
vector<string> fieldNames;
vector<enum FIELD_TYPE> fieldTypes;
vector<string>::iterator it;
int flag=-1;
bool print=true;
for(it=attributes.begin();it!=attributes.end();it++) {
for(int i=0;i<tableSchema.getNumOfFields();i++) {
string temp = *it;
if(tableSchema.getFieldName(i)==temp || tableName+"."+tableSchema.getFieldName(i) == temp)
flag=i;
}
if(flag!=-1) {
fieldNames.push_back(tableSchema.getFieldName(flag));
fieldTypes.push_back(tableSchema.getFieldType(flag));
flag = -1;
}
}
if(attributes.size()==1 && attributes[0] == "*") {
if(whereCondition.empty()) return tableName;
fieldNames = tableSchema.getFieldNames();
fieldTypes = tableSchema.getFieldTypes();
}
Schema dupSchema(fieldNames,fieldTypes);
Relation *relationDup = schemaManager.createRelation(tableName.append("_dup"), dupSchema);
Tuple tuple = relationDup->createTuple();
vector<Tuple>::iterator it1;
Block *block = mainMemory.getBlock(9);
block->clear();
int index=0;
for(int i=0;i<relation->getNumOfBlocks();i++) {
relation->getBlock(i,0);
vector<Tuple> t = mainMemory.getBlock(0)->getTuples();
for(it1=t.begin();it1!=t.end();it1++) {
if(!it1->isNull()){
for(int j=0;j<fieldNames.size();j++) {
if(fieldTypes[j]==INT)
tuple.setField(fieldNames[j],it1->getField(fieldNames[j]).integer);
else
tuple.setField(fieldNames[j],*(it1->getField(fieldNames[j]).str));
}
bool ttp = whereConditionEvaluator(whereCondition, *it1);
if(ttp) {
if(!block->isFull())
block->appendTuple(tuple);
else {
relationDup->setBlock(index,9);
index++;
block->clear();
block->appendTuple(tuple);
}
}
}
}
}
if(index!=relationDup->getNumOfBlocks()-1)
relationDup->setBlock(index, 9);
return tableName;
}