Cursors - SQL

When you write code for a transaction that retrieves a single row of results, you can use a SELECT INTO statement. This is called a singleton SELECT statement. When you write code for a transaction where the result set includes several rows of data, you must declare and use a cursor. A cursor is a mechanism you can use to fetch rows one at a time.

The four API server cursor types supported by SQL Server are: Static cursors Static cursors detect few or no changes but consume relatively few resources while scrolling, although they store the entire cursor in tempdb.   Dynamic cursors Dynamic cursors detect all changes but consume more resources while scrolling, although they make the lightest use of tempdb.   Keyset-driven cursors Keyset-driven cursors lie in between, detecting most changes but at less expense than dynamic cursors.   Forward-only cursors