Cursor Programming Details
Choosing the correct cursor options is an important part of developing a Microsoft® SQL Server™ 2000 application.
Using block cursors can reduce the number of network roundtrips between the client and SQL Server, thereby improving performance. SQL Server may implicitly convert a cursor type if you execute a Transact-SQL statement not supported by the cursor type you requested. SQL Server populates the keyset of a large keyset-driven cursor asynchronously, which shortens the time between when the cursor is opened and when you can fetch the first rows.