topic Re: hashed table in Application Development and Automation Discussions

hashed table

Former Member — Fri, 27 Jul 2007 11:52:44 GMT

how to delete a record from a hashed table.

i know tht we can do with table key.Buti m having some 4 keys.

so i cant delete with table key.

if two key values are satisfied i want to delete tht record how to implement where condition in hashed table.

Thanks in advance

Re: hashed table

varma_narayana — Fri, 27 Jul 2007 12:00:07 GMT

Check out this code.

&----

*& Report ZHASHED *

*& *

&----

*& *

&----

REPORT ZHASHED .

TYPES : BEGIN OF EMP,

ID(3),

NAME(10),

SAL TYPE I,

END OF EMP.

DATA : TAB TYPE HASHED TABLE OF EMP WITH UNIQUE KEY ID.

DATA: WA LIKE LINE OF TAB.

WA-ID = 1.

WA-NAME = 'A'.

WA-SAL = 10000.

INSERT WA INTO TABLE TAB.

WA-ID = 2.

WA-NAME = 'A'.

WA-SAL = 10000.

INSERT WA INTO TABLE TAB.

WA-ID = 3.

WA-NAME = 'A'.

WA-SAL = 10000.

INSERT WA INTO TABLE TAB.

DELETE TAB WHERE ID = 2.

WRITE:/ SY-SUBRC.

LOOP AT TAB INTO WA.

WRITE:/ WA-ID, WA-NAME, WA-SAL.

ENDLOOP.

<b>Reward if Helpful</b>

Re: hashed table

Former Member — Fri, 27 Jul 2007 12:02:57 GMT

Hi,

Hashed table is useful when your have to work with very big internal table and to read it with

"READ TABLE WITH KEY ..."

The time access is constant !

Definition of a Hashed Table:

"Defines the table as one that is managed with an internal hash procedure. You can imagine a hashed table as a set, whose elements you can address using their unique key. Unlike standard and sorted tables, you cannot access hash tables using an index. All entries in the table must have a unique key.

Access time using the key is constant, regardless of the number of table entries.

You can only access a hashed table using the generic key operations or other generic operations (SORT, LOOP, and so on). Explicit or implicit index operations (such as LOOP ... FROM to INSERT itab within a LOOP) are not allowed."

As long as your records has unique key(s), using hash table will give you a huge performance gain when dealing with large dataset. assuming in your case, 10000 record , and if the key is unique, use hash table. The main use of hash tables is for looking up fixed information from a key. So if you have a report that has personnel number and you want to display their name, you could use a hash table.

Thus:

Code:

types: begin of typ_pernr,

pernr like pa0001-pernr,

ename like pa0001-ename,

end of typ_pernr.

data: ls_pernr type typ_pernr,

lt_pernr type hashed table of typ_pernr with unique key pernr.

...

select pernr ename into table lt_pernr from pa0001.

...

loop at itab.

read table lt_pernr with table key pernr = itab-pernr

into ls_pernr.

write: ls_pernr-ename, itab-data.

endloop.

Regards

Re: hashed table

Former Member — Fri, 27 Jul 2007 12:04:22 GMT

thanks .

But i cant give the value statically since mine is field symbol.

How to delete a record from hashed table dynamically with where condition.

Thanks in advance.

Re: hashed table

Former Member — Fri, 27 Jul 2007 12:12:05 GMT

you can delete the rows in the hashed table by using the table key. Kindly refer to the code sample given below,

DATA: BEGIN OF itab_line,

col1 TYPE i,

col2 TYPE i,

END OF itab_line.

DATA itab LIKE HASHED TABLE OF itab_line WITH UNIQUE KEY col1.

DO 5 TIMES.

itab_line-col1 = sy-index.

itab_line-col2 = sy-index * 2.

INSERT itab_line INTO TABLE itab.

ENDDO.

DELETE

DELETE itab WHERE col1 = 3.

LOOP AT itab INTO itab_line.

WRITE: / itab_line-col1, itab_line-col2.

ENDLOOP.

<b>If it helps kindly assign the points...</b>

Regards