Database-table default value for a column in SAP R/3

Question

In the context of my SAP Application I added a column to an existing table and would like to define a default value for it, so that old code working with the table (code that is inserting lines especially) doesn't have to care about the new column - rather I want it to be filled with a predefined default value automatically (only if no value is specified of course).

The DB-system that lies behind is an Oracle-DB, though I have only access to it through the SAP-GUI and the ABAP-SQL.

As our company expert for SAP did not know if this is possible I thought maybe someone here would. So - is this possible and if it is - how?

Edit - Requested Scenario details: The scenario is actually very simple: We have a users-table for our application containing the standard user stuff (name, some setting, Ids, division, a bunch of flags and so on), and I added a column to store a simple setting (the design the user has chosen for his webinterface). It contains simply a name (char 40). That's the column I talked about above and I want the default value for it to be let's say "Default Design".

oracle tag removed as people pointed out that the SAP DB-logic is unreliant to the underlying database — LionC
I suppose you're not using the USR* tables provided by the system itself, so you're not capable of using the provided mechanisms to add custom data to the user data which is perfectly capable of supplying default values? — vwegert
No we're not using system-provided tables - as I read out of your answer that means what I try is not possible. I'll mark your answer and really really thank you. — LionC

vwegert vwegert · Accepted Answer · 2013-04-26T16:43:20

Please, don't even think about doing this on a database level. Seriously. Changes made to the database layer directly will not be visible inside the system and lead to all kinds of strange side effects that will be a nightmare to support. Besides, your changes won't be picked up by the Change and Transport System - you'd have to update the QA and Production systems manually.

If possible, I'd recommend to choose your domain values in a way that the neutral field value (spaces, zero, whatever) corresponds to your default value. If this is not possible, please describe your scenario in detail to get a more specific answer.

The SAP R/3 / ABAP environment does not give you the option of adding default values for a column. You can only choose to force the system to fill the non-NULL default values when adding a column, but this is usually a bad idea. It takes time to modify all the data and insert the default values, and depending on the table size and criticality, this can lead to a production outage. Filling the fields with default values has to be performed by the application server, not the database. In your case, I'd just add the logic in the read-access module, something like

IF my_user-ze_design IS INITIAL.
  my_user-ze_design = co_ze_default_design.
ENDIF.

Database-table default value for a column in SAP R/3

2 Answers