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 |
What is oracle used for?
How to convert characters to times in oracle?
How to bring a tablespace online?
Explain joins in oracle?
What are the commands youd issue to show the explain plan for select
What are the parameters that we can pass through a stored procedure?
What is tns name?
How can windows applications connect to oracle servers?
Why does Oracle not permit the use of PCTUSED with indexes?
What are the roles of dba?
What is Row Chaining ?
What is an Oracle sequence?