Oracle Tutorials

SQL data manipulation statements, including queries that
return only one row. However,
for queries that return more than one row, you must
declare an explicit cursor or use
a cursor FOR loop.

three commands to control the cursor: OPEN, FETCH, and
CLOSE.

initialize the cursor with the OPEN statement, which
identifies the active set.
Then, you use the FETCH statement to retrieve the first
row.
You can execute FETCH repeatedly until all rows have been retrieved.

release the cursor with the CLOSE statement.

DECLARE
CURSOR c1 IS SELECT ename FROM emp;
name1 emp.ename%TYPE;
name2 emp.ename%TYPE;
name3 emp.ename%TYPE;
BEGIN
OPEN c1;
FETCH c1 INTO name1; -- this fetches first row
FETCH c1 INTO name2; -- this fetches second row
FETCH c1 INTO name3; -- this fetches third row
...
CLOSE c1;
END;

four attributes of cursor : %NOTFOUND, %FOUND, %ROWCOUNT, and %ISOPEN

what is SGA.

The SGA is a shared memory region allocated by the
Oracle that
contains Data and control information for one Oracle
Instance.