What is wrong with Cursors?

Question

SQL Server developers consider Cursors a bad practise , except under some circumstances. They believe that Cursors do not use the SQL engine optimally since it is a procedur

Answer 1

From MSDN:Cursor Implementations

Using a cursor is less efficient than using a default result set. In a default result set the only packet sent from the client to the server is the packet containing the statement to execute. When using a server cursor, each FETCH statement must be sent from the client to the server, where it must be parsed and compiled into an execution plan.

If a Transact-SQL statement will return a relatively small result set that can be cached in the memory available to the client application, and you know before executing the statement that you must retrieve the entire result set, use a default result set. Use server cursors only when cursor operations are required to support the functionality of the application, or when only part of the result set is likely to be retrieved.

I'm not an Oracle DBA, so I can't really speak to how the implementations are different. However, from a programming standpoint, set based operations are almost always faster than processing results in a cursor.