Quotes causing problem-- I think

Question

I have below a pl block, all it is supposed to do is replace 111 in (\\APP-MDMDAV-111\%)with 1, Don't know what I am doing wrong. something is wrong for sure may be the whole thing is wrng. Any Suggestions
DECLARE
V_STRING_ORIGIONAL VARCHAR2(100);
V_STRING_NEW VARCHAR2(100);
V_STR1 VARCHAR2(2500);
V_STR2 VARCHAR2(2500);
V_STR3 VARCHAR2(2500);
BEGIN
V_STR1 :='SELECT CONFIG_VALUE FROM EV_CONFIG WHERE CONFIG_VALUE LIKE'|| '''\\APP-MDMDAV-111\%'''||';';
DBMS_OUTPUT.PUT_LINE('ORIGNAL VALUE IS = ' || V_STR1);
EXECUTE IMMEDIATE V_STR1 INTO V_STRING_ORIGIONAL;
V_STR2:='SELECT REPLACE ('||'''||V_STRING_ORIGIONAL||'''||','|| '''111''' || ',' || '''1'''||') FROM DUAL;';
DBMS_OUTPUT.PUT_LINE('NEW VALUE IS = ' || V_STR2);
EXECUTE IMMEDIATE V_STR1 INTO V_STRING_NEW;
V_STR3 := 'UPDATE EV_CONFIG SET CONFIG_VALUE ='||'''||V_STRING_NEW||'''||'WHERE CONFIG_VALUE = '||'''|| V_STRING_ORIGIONAL '''||';';
DBMS_OUTPUT.PUT_LINE('UPDATE STATEMENT IS = ' || V_STR3);
EXECUTE IMMEDIATE V_STR3;
END;

Answer 1

You don't need Dynamic SQL
DECLARE
V_STRING_ORIGIONAL VARCHAR2(100);
V_STRING_NEW VARCHAR2(100);
BEGIN
SELECT CONFIG_VALUE into V_STRING_ORIGIONAL
FROM EV_CONFIG WHERE CONFIG_VALUE LIKE 'APP-MDMDAV-111\%';
select replace(V_STRING_ORIGIONAL  ,111,1) into V_STRING_NEW from dual;
UPDATE EV_CONFIG SET CONFIG_VALUE =V_STRING_NEW
WHERE CONFIG_VALUE = V_STRING_ORIGIONAL;
END;However, you don't need PL/SQL the same can be achieve as follows
UPDATE EV_CONFIG A
SET CONFIG_VALUE =(select replace(CONFIG_VALUE  ,111,1) 
                   from EV_CONFIG B
                   WHERE A.UNIQUE_ID=B.UNIQUE_ID)  -- Assuming table has Primary key or some kind of  Unique id
WHERE CONFIG_VALUE LIKE '\\APP-MDMDAV-111\%'