class sortMerge {
public:
sortMerge(
char *filename1, // Name of heapfile for relation R.
int len_in1, // # of columns in R.
AttrType in1[], // Array containing field types of R.
short t1_str_sizes[], // Array containing size of columns in R.
int join_col_in1, // The join column number of R.
char *filename2, // Name of heapfile for relation S
int len_in2, // # of columns in S.
AttrType in2[], // Array containing field types of S.
short t2_str_sizes[], // Array containing size of columns in S.
int join_col_in2, // The join column number of S.
char* filename3, // Name of heapfile for merged results
int amt_of_mem, // Number of pages available for sorting
TupleOrder order, // Sorting order: Ascending or Descending
Status& s // Status of constructor
);
~sortMerge();The sortMerge constructor joins two relations R and S, represented by the heapfiles filename1 and filename2, respectively, using the sort-merge join algorithm. Note that the columns for relation R (S) are numbered from 0 to len_in1 - 1 (len_in2 - 1). You are to concatenate each matching pair of records and write it into the heapfile filename3.
};
You will need to use the following classes which are given: Sort, HeapFile, and Scan. You will call the Sort constructor to sort the input heapfiles (which means your primary responsibility will be to implement the merging phase of the algorithm). To compare the join columns of two tuples, you will call the function tupleCmp (declared in sort.h). Once a scan is opened on a heapfile, the scan cursor can be positioned to any record within the heapfile calling the Scan method position with an RID argument. The next call to the Scan method getNext will proceed from the new cursor position.