Question

I have a column containing items that can be sorted by the user:

DOC_ID  DOC_Order DOC_Name    1       1        aaa    2       3        bbb    3       2        ccc 

I’m trying to figure out a way to properly initialize DOC_Order when the entry is created. A good value would either be the corresponding DO-CID (since it is autoassigned), or MAX(DOC-ORDER) + 1

After a bit of googling I saw it was possible to assign a scalar function’s return to the default column.

CREATE FUNCTION [dbo].[NEWDOC_Order]  ( ) RETURNS int AS BEGIN  RETURN (SELECT MAX(DOC_ORDER) + 1 FROM DOC_Documents)  END 

But each of my tries using MS SQL Management studio ended in a ‘Error validating the default for column ‘DOC_Order” message.

Any idea of what the exact SQL syntax to assign a function to DEFAULT is?

Answer 1

The syntax to add a default like that would be

alter table DOC_Order  add constraint  df_DOC_Order  default([dbo].[NEWDOC_Order]()) for DOC_Order 

Also, you might want to alter your function to handle when DOC_Order is null

Create FUNCTION [dbo].[NEWDOC_Order]  ( ) RETURNS int AS BEGIN  RETURN (SELECT ISNULL(MAX(DOC_ORDER),0) + 1 FROM DOC_Documents)  END