What WHERE CURRENT OF clause does in a cursor?
Answers were Sorted based on User's Feedback
If you want to UPDATE or DELETE record from table by using cursor which is defined from same table,"WHERE CURRENT OF" clause can be used. We have to create cursor with "FOR UPDATE" clause to use above clause.
The most recent record fetched from the table (by looping of cursor records) should be updated or deleted by using "WHERE CURRENT OF". When a cursor open with FOR UPDATE clause ,cursor's active set will have row level Exclusive Lock. Other sessions can query the table records, and not able to delete/update or SELECT with FOR UPDATE clause.
Example: Want to update value for GRADE column to '1' for the student who has Id = '1'.
Declare
cursor C1 is
select st_id, grade,st_last_name from student where st_id = 3;
for update of grade;
[ variable declaration ……] ;
begin
open C1;
fetch C1 into v_id,v_grade,v_name;
if C1%notfound then
dbms_output.put_line (‘No Record is found.’);
else
update student set grade=1 WHERE CURRENT OF;
COMMIT;
END IF;
CLOSE C1;
end;
| Is This Answer Correct ? | 1 Yes | 0 No |
Answer / kamala k n
return latest fetch row to perform DML on it it is unique
| Is This Answer Correct ? | 0 Yes | 0 No |
How to initialize variables with default values?
What happens to the indexes if a table is recovered?
How to insert a new row into a table in oracle?
What is primefaces used for?
What is the difference between INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL JOIN?
How to sort the query output in oracle?
How are Indexes Update ?
What is the simplest tool to run commands on oracle servers?
Display the number value in Words?
ABOUT IDENTITY?
how many types of index?
Suppose U install the oracle DB either enterprise edition or express edition in ur personal PC, Is there the Database has been created after ur installation if not then where the oracle's all objects with data be stored?