Deciding Column name in UPDATE statement at runtime?

Question

Hi,
Assuming there are 5 columns COLUMN1 through COLUMN5 in TABLE1
In any Update Statement, say:
UPDATE TABLE1 SET COLUMN1='Hi' WHERE COLUMN2='Hello';
Can we decide the COLUMN to bet set at runtime depending on some literal value?
Here in this case, like i get some value in a variable x := 'COLUMN1';, then how can i use an UPDATE statement to following:
UPDATE TABLE1 SET x='Hi' WHERE COLUMN2='Hello';
here x is decided on some logic, i.e. which column is to be updated is decided at runtime.
Please help.
Many thanks in advance.

Answer 1

Hi,
I understood a bit of your code...a 60%..
Better you can see this below example...small and simple example..from this you can understand....and you can solve your problem.. and use of EXECUTE IMMEDIATE...
DECLARE
sql_stmt VARCHAR2(200);
plsql_block VARCHAR2(500);
emp_id NUMBER(4) := 7566;
salary NUMBER(7,2);
dept_id NUMBER(2) := 50;
dept_name VARCHAR2(14) := 'PERSONNEL';
location VARCHAR2(13) := 'DALLAS';
emp_rec emp%ROWTYPE;
BEGIN
EXECUTE IMMEDIATE 'CREATE TABLE bonus (id NUMBER, amt NUMBER)';
sql_stmt := 'INSERT INTO dept VALUES (:1, :2, :3)';
EXECUTE IMMEDIATE sql_stmt USING dept_id, dept_name, location;
sql_stmt := 'SELECT * FROM emp WHERE empno = :id';
EXECUTE IMMEDIATE sql_stmt INTO emp_rec USING emp_id;
plsql_block := 'BEGIN emp_pkg.raise_salary(:id, :amt); END;';
EXECUTE IMMEDIATE plsql_block USING 7788, 500;
sql_stmt := 'UPDATE emp SET sal = 2000 WHERE empno = :1
RETURNING sal INTO :2';
EXECUTE IMMEDIATE sql_stmt USING emp_id RETURNING INTO salary;
EXECUTE IMMEDIATE 'DELETE FROM dept WHERE deptno = :num'
USING dept_id;
EXECUTE IMMEDIATE 'ALTER SESSION SET SQL_TRACE TRUE';
END;
Thanks
Pavan Kumar N