Any cursor, once opened, has an associated result set. The cursor is kept open for a length of time. During that time, the result set associated with the cursor may be changed, either through the cursor itself or, subject to isolation level requirements, by other transactions. Some cursors permit changes to the underlying data to be visible, while others do not reflect these changes. A sensitivity to changes to the underlying data causes different cursor behavior, or cursor sensitivity.
SQL Anywhere provides cursors with a variety of sensitivity characteristics. This section describes what sensitivity is, and describes the sensitivity characteristics of cursors.
This section assumes that you have read Cursors.
Cursor sensitivity example: A deleted row
Cursor sensitivity example: An updated row
Cursor sensitivity and performance
Cursor sensitivity and isolation levels
Requests for SQL Anywhere cursors
Discuter à propos de cette page dans DocCommentXchange.
|Copyright © 2013, SAP AG ou société affiliée SAP - SAP Sybase SQL Anywhere 16.0|