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OpenESQL

Compiling

To compile OpenESQL applications that use a 64-bit Data Source Name (DSN) for 32-bit platforms, and for which you specify the CHECK or DB compiler directive options, you must explicitly create a 32-bit DSN of the same name as the 64-bit DSN. Do this using the ODBC Data Source Administrator (32-bit). The execution process continues to use the 64-bit DSN. This applies to Windows environments (local development) only.

Embedded SQL Statements

Any EXEC SQL statement that specifies a table or column name containing one or more special characters must have that table or column name enclosed in quotes to prevent a preprocessor error. A special character is an ASCII character with a value greater than 128 or a hexadecimal character with a value greater than x"80".

ODBC

When using Oracle's ODBC driver, array fetches and some scrolling fetches might produce inconsistent behavior if you change the array size between fetches. To overcome this, build your application with SQL(NORESULTARRAY). When this is set, OpenESQL performs single row fetches under the covers, bypassing this limitation.

OpenESQL ODBC Native Runtime

OpenESQL applications are optimized for performance by default, with OpenESQL now implicitly setting the BEHAVIOR compiler directive to OPTIMIZED; with previous products, the BEHAVIOR compiler directive was implicitly set to UNOPTIMIZED. This change can impact program behavior as follows:

Programs that include the SET SCROLLOPTION or SET CONCURRENCY EXEC SQL statements fail to compile. For affected programs, do one of the following:
- Before compiling, set the BEHAVIOR compiler directive to UNOPTIMIZED. While this is the simplest solution, we do not recommended it due to the possibility of degraded performance.
- Remove all SET SCROLLOPTION and SET CONCURRENCY statements and, if necessary, modify the DECLARE CURSOR statement to include appropriate parameters to yield the same behavior. For example, to elicit the same behavior as the SET SCROLLOPTION statement, use the following DECLARE CURSOR statement:
```
EXEC SQL DECLARE cursorname SCROLL LOCK CURSOR FOR…
```
  By default, cursors are forward and read only. If this is the desired behavior, you can safely remove the SET statements with no further action required. However, we recommend as a matter of good practice to always include FOR READ ONLY or FOR UPDATE in cursor declarations to ensure that the default behavior is always explicit. We recommended this solution.
The OPTIMIZED setting does not make ambiguous cursors updateable. Therefore, applications that expect cursors to be updateable, according to the default ANSI standards for Embedded SQL, are affected. In this case, we recommend that you set the BEHAVIOR compiler directive option to ANSI.
The OPTIMIZED setting does not assume scrollable cursors. Therefore, applications that expect cursors to be scrollable are affected. In these cases, we recommend that you modify your DECLARE CURSOR statements to compensate, as specified above.

Important: If you do not want to take advantage of the performance gains provided by this change in implicit behavior, use the OpenESQL Configuration Utility to change the implicit value of the BEHAVIOR compiler directive back to UNOPTIMIZED. For details, see OpenESQL Embedded SQL Cursor Behavior and Performance.

PostgreSQL Recommendations

When a negative SQL code is returned to a calling application, PostgreSQL aborts transactions implicitly unless you change the default behavior of the ODBC driver. To work around this shortcoming, consider modifying the psqlODBC driver Configuration Options as follows:

On Advanced Options page 1, check Use Declare/Fetch.
On Advanced Options page 2, set the Level of rollback on errors option to Statement.

Programming

The program name for programs that use OpenESQL is restricted to 30 characters in length. This enables cursors to always be correctly associated with the programs that create them.