OpenESQL Embedded SQL Cursor Behavior and Performance

In releases of Enterprise Developer earlier than version 2.1, by default, OpenESQL handled ambiguously declared embedded SQL cursors, that is, those declared without a FOR READONLY or FOR UPDATE clause, by making them updateable, scrollable, and capable of retrieving database locks — the maximum functionality. Unfortunately, this degraded performance for most applications. Also in these earlier releases, it was difficult and tedious to make robust changes to cursor characteristics because it often required modifying source code by either adding EXEC SQL SET statements or modifying existing EXEC SQL DECLARE CURSOR statements.

Starting with Enterprise Developer 2.1, by default, OpenESQL began handling ambiguously declared embedded SQL cursors by making them forward and readonly, and incapable of retrieving locks. This change improved performance and efficiency, optimizing OpenESQL just as most DBMS SQL cursor access plans do.

You can further optimize OpenESQL by using the BEHAVIOR directive, which enables you to change your embedded SQL cursor characteristics without changing any code in your SQL application sources.

Enterprise Developer provides the OpenESQL Configuration Utility to assist you in setting the BEHAVIOR directive and primitive directive defaults for your applications. See OpenESQL Configuration Utility for Default SQL Cursor Behavior for details.