Why cursor is bad for performance?

Why cursor is bad for performance?

Because cursors take up memory and create locks. What you are really doing is attempting to force set-based technology into non-set based functionality.

What is ref cursor?

A ref cursor is a variable, defined as a cursor type, which will point to, or reference a cursor result. The advantage that a ref cursor has over a plain cursor is that is can be passed as a variable to a procedure or a function. The REF CURSOR can be assigned to other REF CURSOR variables.

What is an advantage of cursor in Oracle?

Advantages and Disadvantages of Cursor in Oracle Cursor fetches the data Row wise so Row Wise validation is possible using the cursor. It retrieves one row at a time, unlike SQL select query which selects all rows at a time. It is faster than While Loop but does have more overhead.

What are the drawbacks of implicit cursors?

The implicit cursor has the following drawbacks:

• It is less efficient than an explicit cursor (in PL/SQL Release 2.2 and earlier)
• It is more vulnerable to data errors.
• It gives you less programmatic control.

What are the disadvantages of using the cursor?

Each time when a row is fetched from the cursor it may result in a network round trip. This uses much more network bandwidth than the execution of a single SQL statement like SELECT or DELETE etc that makes only one round trip. Repeated network round trips can degrade the speed of the operation using the cursor.

When to use a cursor in a database?

Cursors are used when the user needs to update records in a singleton fashion or in a row by row manner, in a database table. Beside above, which is better cursor or while loop?

When do you use a cursor in Excel?

Cursors can provide the first few rows before the whole result set is assembled. Without using cursors, the entire result set must be delivered before any rows are displayed by the application.

Which is better a while loop or a cursor?

In terms of what it is doing, a while loop and a cursor both do the same thing, they operate on one row at a time. A lot of people when trying to remove cursor-based code, simply replace it with a while loop, in the hope that it will run faster, because it’s not a *nasty* cursor.