A novice for help, which master can tell? PS: I haven't.
In the PB wrote this code:

Ls_sql="if not the exists (select q from sysobjects where xtype='D' and name='DF_xssp_txm3') ~ r" + & amp;
"The Alter table XSSP add constraint DF_xssp_txm3 Default (' ') for txm3 ~ r" + & amp;
"The Update XSSP set txm1=rtrim (txm1), txm2=rtim (txm2), txm3=rtrim (txm3)"

The sqlca. The autocommit=true
The execute immediate: ls_sql;
If the sqlca. Sqlcode & lt;> 0 then
Ls_sqlerr=sqlca. Sqlerrtext
The rollback.
Messagebox (' prompt ', 'failed to initialize ~ r + ls_sqlerr)
End the if
The sqlca. The autocommit=false

Even through several database testing, but by the customer side, after the execution is an error. The sqlca. Sqlerrtext value is "Request has had been cancelled". Don't know this error is caused by what. Guide the warrior.