Need help with trigger for whitespace and caps validation

Question

I need to create a table trigger that will generate an error whenever a specific column does not contain all caps or has whitespace when records are either inserted or updated. I'm new to writing SQL, so any help is appreciated!

Answer 1

In 10g
SQL> create or replace trigger trigg_sample
  2  before update or insert on sample
  3  for each row
  4  declare
  5  lv_pos number;
  6  begin
  7  select regexp_instr(:new.col1,'[a-z|( )]') into lv_pos from dual;
  8  if lv_pos > 0 then
  9  raise_application_error(20000,'The column contains lowercase or white space characters');
10  end if;
11  end;
12  /
Trigger created.
SQL> desc sample;
Name                                      Null?    Type
COL1                                               VARCHAR2(20)
SQL> insert into sample values('DFD') ;
1 row created.
SQL> insert into sample values('dfdfd') ;
insert into sample values('dfdfd')
ERROR at line 1:
ORA-21000: error number argument to raise_application_error of 20000 is out of
range
ORA-06512: at "XLS_ADMIN.TRIGG_SAMPLE", line 6
ORA-04088: error during execution of trigger 'XLS_ADMIN.TRIGG_SAMPLE'
SQL> insert into sample values('DFDF ') ;
insert into sample values('DFDF ')
ERROR at line 1:
ORA-21000: error number argument to raise_application_error of 20000 is out of
range
ORA-06512: at "XLS_ADMIN.TRIGG_SAMPLE", line 6
ORA-04088: error during execution of trigger 'XLS_ADMIN.TRIGG_SAMPLE'
SQL>