A little urgent when to use binary search.

Question

Hi evryone,
Plz let me know under what kind of conditions can we use binary search addition cause if I use it for every read statement the database acees in se30 goes higher than normal.
If i randomly select only a few big read table statements the database acees in se30 goes is slightly lesser.
But I some how dont know where to use binary search and where not to with read statements.
Expecting an early reply.
Rgds,
Anu

Answer 1

hi,
If you read entries from standard tables using a key other than the default key, you can use a binary search instead of the normal linear search. To do this, include the addition BINARY SEARCH in the corresponding READ statements.
READ TABLE <itab> WITH KEY <k1> = <f1>... <kn> = <fn> <result>
                                                       BINARY SEARCH.
The standard table must be sorted in ascending order by the specified search key. The BINARY SEARCH addition means that you can access an entry in a standard table by its key as quickly as you would be able to in a sorted table.
REPORT demo_int_tables_read_index_bin.
DATA: BEGIN OF line,
        col1 TYPE i,
        col2 TYPE i,
      END OF line.
DATA itab LIKE STANDARD TABLE OF line.
DO 4 TIMES.
  line-col1 = sy-index.
  line-col2 = sy-index ** 2.
  APPEND line TO itab.
ENDDO.
SORT itab BY col2.
READ TABLE itab WITH KEY col2 = 16 INTO line BINARY SEARCH.
WRITE: 'SY-SUBRC =', sy-subrc.
The output is:
SY-SUBRC =    0
The program fills a standard table with a list of square numbers and sorts them into ascending order by field COL2. The READ statement uses a binary search to look for and find the line in the table where COL2 has the
reward if useful.
Thanks,
Madhukar