const int projCnt, // Number of attributes in the projection

const AttrDesc attrDescArray[], // The projection list (as AttrDesc)

const AttrDesc& attrDesc1, // The left attribute in the join predicate

const Operator op, // Predicate operator

const AttrDesc& attrDesc2, // The right attribute in the join predicate (INDEXED)

const int reclen) // Length of a tuple in the output relation

{

cout << "Algorithm: Indexed NL Join" << endl;

AttrDesc* r;

int num;

Status status = attrCat->getRelInfo(result, num, r);

if(status != OK) return status;

// Load heap 1

HeapFileScan heap1 = HeapFileScan(attrDesc1.relName, status);

if (status != OK) return status;

// Load heap 2

HeapFileScan heap2 = HeapFileScan(attrDesc2.relName, status);

if (status != OK) return status;

// Open output heap

HeapFile heapOut = HeapFile(result, status);

if (status != OK) return status;

// Get size of output record

int size = 0;

for (int x = 0; x < projCnt; x++)

{

size += attrDescArray[x].attrLen;

}

// Create/find the index (checked to ensure indexed before entering this fn)

Index index = Index(attrDesc2.relName, attrDesc2.attrOffset, attrDesc2.attrLen, (Datatype)attrDesc2.attrType, 1, status);

if (status != OK) return status;

//Start Join

RID rid, rid1, rid2;

Record record1, record2;

while(heap1.scanNext(rid1, record1) == OK)

{

char* data1 = (char *) record1.data;

// Update Heapfile Scan for Next Loop

heap2 = HeapFileScan(attrDesc2.relName, status);

if(status != OK) return status;

// Restart the Index Scan for Next Loop

status = index.startScan((char *) record1.data + attrDesc1.attrOffset);

if(status != OK) return status;

while(index.scanNext(rid2) == OK)

{

status = heap2.getRandomRecord(rid2, record2);

if(status != OK) return status;

char* data2 = (char *) record2.data;

// Compare the values stored in both records

int valueDif = matchRec(record1, record2, attrDesc1, attrDesc2);

if(!valueDif)

{

// Add to output heap

Record record;

record.data = malloc(size);

record.length = size;

//Need to check through attrDescArray to find outside heap attrDescs

for(int i = 0; i < projCnt; i++)

{

AttrDesc tempAttr = attrDescArray[i];

//Insert from attrDesc1

if( !strcmp(attrDesc1.relName, tempAttr.relName))

{

memcpy(((char*) record.data) + r[i].attrOffset, data1 + tempAttr.attrOffset, tempAttr.attrLen);

}

else

{

memcpy(((char*) record.data) + r[i].attrOffset, data2 + tempAttr.attrOffset, tempAttr.attrLen);

}

}

// Now insert the record into the output

status = heapOut.insertRecord(record, rid);

if(status != OK) return status;

}

}

// End the scan and restart it again next iteration

status = index.endScan();

if(status != OK) return status;

}

status = heap1.endScan();

if(status != OK) return status;

return OK;