topic Re: who does hash algorithm work? in Application Development and Automation Discussions

who does hash algorithm work?

Former Member — Wed, 25 Jun 2008 12:21:17 GMT

Hi,

READ staments in ABAP use a hash algorithm to search information in a hashed internal table, and the runtime is independent of the number of table entries.

So, Who does hash algorithm work?

Thanks.

Re: who does hash algorithm work?

JozsefSzikszai — Wed, 25 Jun 2008 12:23:24 GMT

hi,

The hash algorithm is built up by the system automatically. You don't have to care about that, you just have to define the internal table TYPE HASHED.

hope this helps

Re: who does hash algorithm work?

Former Member — Wed, 25 Jun 2008 13:33:47 GMT

read about hash functions in wikipedia or something similar, these are special functions.

A hash function can calculate from the key the address (line number) where the record is stored. Every insert changes the function a bit, access is like an index access only slightly slower as the calculation takes also time, we are talking of some microseconds.

You need to know the complete key, otherwise iit will noot work at all, and the read will scan the full table.

Siegfried

Re: who does hash algorithm work?

Former Member — Wed, 25 Jun 2008 13:49:50 GMT

http://fr.wikipedia.org/wiki/Table_de_hachage#Fonction_de_Hachage