SQL Server Query Performance Tuning,Fourth Edition

CHAPTER 22

Row-by-Row Processing

It is common to find database applications that use cursors to process one row at a time. Developers tend to think about processing data in a row-by-row fashion. Oracle even uses something called cursors as a high-speed data access mechanism. But cursors in SQL Server are different. Because data manipulation through a cursor in SQL Server incurs significant additional overhead, database applications should avoid using cursors. T-SQL and SQL Server are designed to work best with sets of data, not one row at a time. Jeff Moden famously termed this type of processing RBAR (pronounced, ree-bar), meaning row by agonizing ...