Cursors are a powerful data management tool. They allow client applications to update individual result rows while processing a result set. A server-side cursor, sometimes called a “native cursor,” is a cursor that exists on Sybase Adaptive Server® Enterprise (called “SQL Server” in versions prior to 11.5).
Client-Library fully supports server-side cursors, providing a call-level interface that allows client applications to declare, open, and manipulate server-side cursors.
DB-Library does not support server-side cursors. Instead, it supports a type of cursor emulation known as “client-side cursors.” Client-side cursors do not correspond to actual Adaptive Server cursors. Instead, DB-Library buffers rows internally and performs all necessary keyset management, row positioning, and concurrency control to manage the cursor.
Client-Library’s cursor functionality replaces DB-Library’s row buffering functionality, which carries a memory and performance penalty because each row in the buffer is allocated and freed individually.
