Supply error messages and a user guide for your functions

Plan the user-guide and error messages for the access-method purpose functions that you are providing.

As you plan access-method purpose functions, familiarize yourself with the following information:
  • The SQL statement syntax in the Informix® Guide to SQL: Syntax
  • The Informix Guide to SQL: Tutorial and the Informix Database Design and Implementation Guide

These documents include examples of HCL Informix SQL statements and expected results, which the SQL user consults.

The user of your access method will expect the SQL statements and keywords to behave as documented in the database server documentation. If the access method causes an SQL statement to behave differently, you must provide access-method documentation and messages to alert the user to these differences.

In the access-method user guide, list all SQL statements, keywords, and options that raise an exception if an end user attempts to execute them. Describe any features that the access method supports in addition to the standard SQL statements and keywords.

Create callback functions to respond to database server exceptions, as Handle the unexpected describes. Raise access-method exceptions for conditions that the database server cannot detect. Use the following sections as a checklist of items for which you supply user-guide information, callback functions, and messages.