User defined function to set a default value of a column

Question

Hi All
Can we use user defined function to set a default value of a column ??
for example:
create or replace  function test1  return number is
begin
return 10;
end;
create table testt
(id  as test1,
  name varchar2(20));
error:
ORA-02000: missing ( keywordThanks
Ashwani

Answer 1

174313 wrote:
MichaelS for showing example to use function in table ddl , otherwise i was thinking we cannot use function in table ddl as per error I received.That was an example of a virtual column.
ORA-04044: procedure, function, package, or type is not allowed hereUsing PL/SQL code like that raises 2 basic problems. If that PL/SQL code for the calculating the column default breaks, what happens to the SQL insert statements against that table. These will need to fail as the table definition depends on the PL/SQL code. This is problematic as this dependency simply increases the complexity of the SQL object.
The 2nd issue is performance. PL/SQL code needs to be executed by the PL/SQL engine. This means a context switch from the SQL engine to the PL/SQL engine in order to determine the default value for that column. Context switching is a performance overhead.
So even if it was possible to use a PL/SQL function as parameter for the SQL default clause, I would not be that keen to use it.