Cursor sensitivity overview

SQL Anywhere cursors are classified by their sensitivity to changes in the underlying data. In particular, cursor sensitivity is defined in terms of which changes are visible.

  • Insensitive cursors   The result set is fixed when the cursor is opened. No changes to the underlying data are visible. See Insensitive cursors.

  • Sensitive cursors   The result set can change after the cursor is opened. All changes to the underlying data are visible. See Sensitive cursors.

  • Asensitive cursors   Changes may be reflected in the membership, order, or values of the result set seen through the cursor, or may not be reflected at all. See Asensitive cursors.

  • Value-sensitive cursors   Changes to the order or values of the underlying data are visible. The membership of the result set is fixed when the cursor is opened. See Value-sensitive cursors.

The differing requirements on cursors place different constraints on execution, and so, performance. See Cursor sensitivity and performance.