How can I run beginddl in PL/SQL Developer

Question

Here's my script:
begin
execute dbms_wm.beginddl('MyTable');
ALTER TABLE MyTable ADD NewColumn1 VARCHAR2(200)
execute dbms_wm.commitddl('MyTable');
end;
I got the following error:
ORA-06550: line 2, column 11:
PLS-00103: Encountered the symbol "DBMS_WM" when expecting one of the following:
:= . ( @ % ; immediate
The symbol ":=" was substituted for "DBMS_WM" to continue.
ORA-06550: line 3, column 3:
PLS-00103: Encountered the symbol "ALTER" when expecting one of the following:
( begin case declare end exception exit for goto if loop mod
null pragma raise return select update while with
<an identifier> <a double-quoted delimi
What should I do then?
Thanks.

Answer 1

in PL/SQL scripts you just omit the "execute". and for the SQL you need to put an execute before it.
so your script would be:
begin
  dbms_wm.beginddl('MyTable');
  execute immediate 'ALTER TABLE MyTable ADD NewColumn1 VARCHAR2(200)';
  dbms_wm.commitddl('MyTable');
end;apart from that, you should be modifying MyTable_LTS in your DDL session.
regards,
Andreas