DB Inc.
Memo ID: R07
Name of R&D group: KKS
Attended members: Ki-Hwan Kim, Dong-Shin Kim, Dong-Man Shin
Unattended members:
Name of the person to prepare the memo: Dong-Shin Kim
Summary
SQL select program.
1. In Assignment, our program was just work for single search key value. This
Assignment requires for range value so we need fix this part.
2. Procedure
a. Read catalog file : we need to check whether index exists or not and to get
position of column. If index exits go to index file and then get page
number and slot number. If no index case, go to first page of heap file and
check all record.
b. Hash index : If we use hash base index, we may not use list fetch which is
guarantee good performance for range search key value since few I/O,
performance may be slower than B+-Tree index and faster than no index.
c. B+-Tree index: If we use this index, we need to implement two parts. One
is internal node and the other part is leaf part. If data is big, internal node
size will be also big. Delete index function is difficult since we must
consider balance in this tree but this assignment is no requirement for this
part so we just concentrate on insert and search.
3. Consideration
a. In assignment, we use variable length page format so performance is
slower than fixed length page format.
b. The purpose of using index is better performance for searching. It means
program guarantee minimum I/O.
c. We need to deal char type. If we want distinct value of char[40] we need
to huge size of memory for just one string so we must find some good
function which can change from char value into some integer.
d. In this assignment, we will use same page size which is 4kb and same
hash function which is linear hash index.
e. In Previous assignment, we implemented read function as part of main
function. This time we will implement this part as a class or function.