ORA-06502: PL/SQL: numeric or value error: character string buffer too small

I tried the following code different ways, like by taking out the while or the if, but when I put both together (if and while), I always get the error at the end...

undefine numero
set serveroutput on
accept numero prompt 'Type # between 100 and 999: '
declare i number:=1; a char(25); b char(1); c varchar2(10); d number;
begin c := &numero; d := length(c); b := substr(c, i, 1); while i <= d loop if b = '1' then a:= a||'one '; end if; i := i+1; end loop; dbms_output.put_line('The number is '||a);
end;
/

ERROR:

ORA-06502: PL/SQL: numeric or value error: character string buffer too small
ORA-06512: at line 13
06502. 00000 - "PL/SQL: numeric or value error%s"

FIXED by changing how I declared the variable "a" to:

a varchar2(2000);

*Notice that here, the significant change is to use VARCHAR2 instead of CHAR (not the bigger length). According to @user272735 's answer, that's the key.

3 Answers

PL/SQL: numeric or value error: character string buffer too small

is due to the fact that you declare a string to be of a fixed length (say 20), and at some point in your code you assign it a value whose length exceeds what you declared.

for example:

myString VARCHAR2(20);
myString :='abcdefghijklmnopqrstuvwxyz'; --length 26

will fire such an error

CHAR is a fixed-length data type that uses as much space as possible. So a:= a||'one '; will require more space than is available. Your problem can be reduced to the following example:

declare v_foo char(50);
begin v_foo := 'A'; dbms_output.put_line('length of v_foo(A) = ' || length(v_foo)); -- next line will raise: -- ORA-06502: PL/SQL: numeric or value error: character string buffer too small v_foo := v_foo || 'B'; dbms_output.put_line('length of v_foo(AB) = ' || length(v_foo));
end;
/

Never use char. For rationale check the following question (read also the links):

• Oracle datatype: Should I use VARCHAR2 or CHAR

This may also happen if you have a faulty or accidental equation in your csv file. i.e - One of the cells in your csv file starts with an equals sign (=) (An excel equation) which will, in turn throw an error. If you fix, or remove this equation by getting rid of the equals sign, it should solve the ORA-06502 error.