ORA-01403: No Data found WHY? - oracle

Question

I have declared the following procedure:
CREATE OR REPLACE PROCEDURE MODIFY_NOT_NULL(
v_tbName IN VARCHAR2,
v_cName IN VARCHAR2,
v_defaultValue IN VARCHAR2 )
IS
v_is_null VARCHAR2(1);
BEGIN
SELECT nullable INTO v_is_null
FROM USER_TAB_COLUMNS
WHERE TABLE_NAME = v_tbName
AND COLUMN_NAME = v_cName;
IF v_is_null = 'Y' THEN
EXECUTE IMMEDIATE ('ALTER TABLE ' || v_tbName
|| ' MODIFY (' || v_cName
|| ' DEFAULT ' || v_defaultValue
|| ' NOT NULL )');
END IF;
END;
However when I execute my code:
BEGIN
modify_not_null('TABLE_NAME', 'COLUMN_NAME ' ,'0');
END;
/
I am getting a
"ORA-01403: No Data Found"
This exception will be usually thrown if the "SELECT INTO" statement does not return any value, however I will always get a value when I execute this:
Select nullable
from USER_TAB_COLUMNS
WHERE table_name = 'TABLE_NAME'
AND column_name = 'COLUMN_NAME';
When I execute the code above, I get "N" or "Y" as a result. So I always get a result. I don't know why this exception is thrown

Answer 1

Your call contains a trailing space:
modify_not_null('TABLE_NAME', 'COLUMN_NAME ' ,'0');
^
So proc throws no data found because 'COLUMN_NAME ' != 'COLUMN_NAME'
Use upper(trim(v_cName)) to prevent typos causing errors. Apply on all parameters.

Answer 2

You are passing v_defaultValue param to column name.
Change procedure to
SELECT nullable INTO v_is_null
FROM USER_TAB_COLUMNS
WHERE TABLE_NAME = v_tbName AND COLUMN_NAME = v_cName ;

Answer 3

Before your SELECT .... INTO, you have to make sure that there is something to select. Because depending on what user you are, and what parameters you give, there may be no data in your table.
A simple way would be to have a COUNT at the beginning before the SELECT:
CREATE OR REPLACE PROCEDURE MODIFY_NOT_NULL(
v_tbName IN VARCHAR2,
v_cName IN VARCHAR2,
v_defaultValue IN VARCHAR2 )
IS
v_is_null VARCHAR2(1);
v_count number;
BEGIN
-- added select count
SELECT count(1) INTO v_count FROM USER_TAB_COLUMNS WHERE TABLE_NAME = trim(v_tbName) AND COLUMN_NAME = trim(v_cName);
-- added if v_count=1
if v_count = 1 then
SELECT nullable INTO v_is_null FROM USER_TAB_COLUMNS WHERE TABLE_NAME = trim(v_tbName) AND COLUMN_NAME = trim(v_cName);
IF v_is_null = 'Y' THEN
EXECUTE IMMEDIATE ('ALTER TABLE ' || v_tbName || ' MODIFY (' || v_cName || ' DEFAULT ' || v_defaultValue || ' NOT NULL )');
END IF;
-- added
end if;
END;
/
Share and enjoy

Answer 4

stay classy :)
create or replace procedure modify_not_null(v_tbName in varchar2,
v_cName in varchar2,
v_defaultValue in varchar2) is
cursor c_tbl(cp_tbname in varchar2,
cp_cname in varchar2) is
select nullable
from user_tab_columns
where table_name = upper(cp_tbname)
and column_name = upper(cp_cname);
l_tbl c_tbl%rowtype;
begin
open c_tbl(cp_tbname => v_tbName,
cp_cname => v_cName);
fetch c_tbl into l_tbl;
close c_tbl;
if l_tbl.nullable = 'Y' then
execute immediate 'alter table ' || v_tbName || ' modify (' || v_cName ||
' default ' || v_defaultValue || ' not null )';
end if;
exception
when others then
raise_application_error(-20000, dbms_utility.format_error_stack);
end modify_not_null;