pl sql and dynamic sql - dynamic

Question

I am trying to create some dynamic sql using the following code block
firstSqlStatement := true;
updateText := 'UPDATE T_EMPLOYEES SET ';
if FIRSTNAME IS NOT NULL and FIRSTNAME > 0 THEN
updateText:=updateText || ' firstName=' || FIRSTNAME || ' ';
firstSqlStatement := false;
end if;
if MIDDLENAME IS NOT NULL and length(MIDDLENAME) > 0 THEN
if firstSqlStatement = false THEN
updateText:=updateText || ',';
end if;
updateText:=updateText || ' middleName=' || MIDDLENAME || ' ';
firstSqlStatement := false;
end if;
updateText:=updateText
|| ' where upper(id)=upper(' || ID ||');';
DBMS_OUTPUT.put_line(updateText);
EXECUTE IMMEDIATE updateText;
The statement never executes properly as there are missing single quotes around values.
Any ideas what i can do to make this small example work or is there any better way of doing this?

Answer 1

firstSqlStatement := true;
updateText := 'UPDATE T_EMPLOYEES SET ';
if FIRSTNAME IS NOT NULL and FIRSTNAME > 0 THEN
updateText:=updateText || ' firstName=''' || FIRSTNAME || ''' ';
firstSqlStatement := false;
end if;
if MIDDLENAME IS NOT NULL and length(MIDDLENAME) > 0 THEN
if firstSqlStatement = false THEN
updateText:=updateText || ',';
end if;
updateText:=updateText || ' middleName=''' || MIDDLENAME || ''' ';
firstSqlStatement := false;
end if;
updateText:=updateText || ' where upper(id)=upper(' || ID || ');';
DBMS_OUTPUT.put_line(updateText);
EXECUTE IMMEDIATE updateText;
use '''

Answer 2

Maybe you can do it this way.
declare
ll_employee_id number := 10;
lv_firstname varchar2(30) := 'Thomas';
lv_middlename varchar2(30) := null;
begin
update t_employees
set firstname = decode(lv_firstname, null, firstname, lv_firstname),
middlename = decode(lv_middlename, null, middlename, lv_middlename)
where employee_id = ll_employee_id;
end;

Answer 3

DECLARE
my_error exception;
sql_stmt VARCHAR2 (500);
v_char_field VARCHAR2 (500);
v_number_field NUMBER;
v_stmt_number NUMBER;
BEGIN
sql_stmt := 'UPDATE TABLE';
IF 1 = 1 -- REPLACE WITH CONDITION FOR SELECTION FIELD
THEN
sql_stmt := sql_stmt || 'field_1 = :1';
v_stmt_number := 1;
ELSIF 1 = 1 -- REPLACE WITH CONDITION FOR SELECTION FIELD
THEN
sql_stmt := sql_stmt || 'field_2 = :1';
v_stmt_number := 2;
ELSE
DBMS_OUTPUT.put_line ('Field unmanaged');
RAISE my_error;
END IF;
IF 1 = 1 -- REPLACE WITH CONDITION FOR SELECTION TYPE FIELD
THEN
EXECUTE IMMEDIATE sql_stmt USING v_char_field;
ELSIF 1 = 1 -- REPLACE WITH CONDITION FOR SELECTION TYPE FIELD
THEN
EXECUTE IMMEDIATE sql_stmt USING v_number_field;
ELSE
DBMS_OUTPUT.put_line ('Type Field unmanaged');
RAISE my_error;
END IF;
DBMS_OUTPUT.PUT_LINE ('STATEMENT NUMBER : ' || v_stmt_number);
DBMS_OUTPUT.PUT_LINE ('TOTAL RECORD UPDATE : ' || SQL%ROWCOUNT);
EXCEPTION
WHEN my_error
THEN
NULL;
WHEN OTHERS
THEN
DBMS_OUTPUT.PUT_LINE ('ERROR :' || SQLERRM);
END;
You can use multiple selections to compose your statement for selection fields to be updated and for the type.