Using hash tables for fast lookup

Using hash tables for fast lookup

If you have an internal table in your program which is used solely for lookup, it is good programming practice to use a hash table. The example below shows this, in combination with a method for buffering SELECT SINGLE results.

    Requires Free Membership to View

    When you register, you will start receiving targeted emails from my award-winning team of editorial writers. Our goal is to keep you informed on the hottest topics and biggest challenges faced by SAP professionals today.

    Hannah Smalltree, Editorial Director

    By submitting your registration information to SearchSAP.com you agree to receive email communications from TechTarget and TechTarget partners. We encourage you to read our Privacy Policy which contains important disclosures about how we collect and use your registration and other information. If you reside outside of the United States, by submitting this registration information you consent to having your personal data transferred to and processed in the United States. Your use of SearchSAP.com is governed by our Terms of Use. You may contact us at webmaster@TechTarget.com.


 

*&---------------------------------------------------------------------*
*&      Form  select_dispo
*&---------------------------------------------------------------------*
*       Get MRP controller and in-house production time from material 
*       and plant
*----------------------------------------------------------------------*
*      --> MATNR  Material
*      --> RESWK  Plant
*      <-- DISPO  MRP controller
*      <-- DZEIT  In-house production time
*----------------------------------------------------------------------*
form select_from_marc using matnr werks dispo dzeit.

  types: begin of mrp_lookup_type,
           matnr like marc-matnr,
           werks like marc-werks,
           dispo like marc-dispo,
           dzeit like marc-dzeit,
         end of mrp_lookup_type.

* Define static hashed table to hold results
  statics: st_mrp type hashed table of mrp_lookup_type
                  with unique key matnr werks.

  data: l_wa_mrp type mrp_lookup_type.

  clear dzeit.

* See if data is in the table
  read table st_mrp into l_wa_mrp with table key matnr = matnr
                                                 werks = werks.

* If not in table, get it from the database
  if not sy-subrc is initial.

    select single dispo dzeit from marc
        into corresponding fields of l_wa_mrp-dispo
        where matnr eq matnr
          and werks eq werks.

* Insert into table
    l_wa_mrp-matnr = matnr.
    l_wa_mrp-werks = werks.
    insert l_wa_mrp into table st_mrp.
  endif.

  dispo = l_wa_mrp-dispo.                      " MRP Controller
  dzeit = l_wa_mrp-dzeit.                      " Inhouse production time
endform.                    " select_from_marc

This was first published in June 2001

Join the conversationComment

Share
Comments

    Results

    Contribute to the conversation

    All fields are required. Comments will appear at the bottom of the article.

    Disclaimer: Our Tips Exchange is a forum for you to share technical advice and expertise with your peers and to learn from other enterprise IT professionals. TechTarget provides the infrastructure to facilitate this sharing of information. However, we cannot guarantee the accuracy or validity of the material submitted. You agree that your use of the Ask The Expert services and your reliance on any questions, answers, information or other materials received through this Web site is at your own risk.