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Operations on Records

Simplest operation to access a record via its RID: 

Record get_record(RecordId rid) {
    Page buf = request_page(relId(rid), pageNum(rid));
    return get_record_from_page(buf, recNum(rid));
}

where  TupleId = RecordId = (RelId, PageNum, TupIndex)

Gives a sequence of bytes, which needs to be "tuple-fied", e.g. 

Record r = get_record(rid)
Tuple t = makeTuple(rel,rec)

Requires knowledge of relation schema (rel)