Substr function fails

Question

hi there, can anyone tell me why a simple substr would throw an error if the target varchar assignment isn't three characters larger than the length provided to the substr function?
can anyone tell me why this:
declare
v_legal varchar2(200);
v_disp_trans_sid integer := 850500;
begin
v_legal := SUBSTR(Ttls_Common.build_parcel_string(v_disp_trans_sid),1,200);
dbms_output.put_line('v_legal is '||length(v_legal)||' characters.');
end;
causes this even though the assignment is substr to 200:
declare
ERROR at line 1:
ORA-06502: PL/SQL: numeric or value error: character string buffer too small
ORA-06512: at line 7
yet once i increase the size of the target varchar by three characters it works:
declare
v_legal varchar2(203);
v_disp_trans_sid integer := 850500;
begin
v_legal := SUBSTR(Ttls_Common.build_parcel_string(v_disp_trans_sid),1,200);
dbms_output.put_line('v_legal is '||length(v_legal)||' characters.');
end;
causes:
v_legal is 200 characters.
PL/SQL procedure successfully completed.

Answer 1

user521233 wrote:
my character set:Yes, UTF8 is multi-byte. Now check NLS_LENGTH_SEMANTICS:
select value from nls_session_parameters where parameter = 'NLS_LENGTH_SEMANTICS';Most likely it is set to BYTE. If so, as I already noted, you can explicitly specify:
v_legal varchar2(200 char);or you can set lenght semantics for your session to characters instead of bytes
ALTER SESSION SET NLS_LENGTH_SEMANTICS=CHAR;or you could set it to CHAR once for the instance:
ALTER SYSTEM SET NLS_LENGTH_SEMANTICS=CHAR;and bounce th instance.
SY.