Generic Categories of ODBC Errors

• Microsoft Visual FoxPro for Windows, versions 3.0 and 3.0b

SUMMARY

This article provides a generic description for each of three categories of ODBC errors including typical causes and the type of error trapping that can be used to trap for that type of error.

MORE INFORMATION

There are three types of error cases in connectivity issues with ODBC:

• FoxPro Errors
• ODBC Errors
• Connectivity Warnings

FoxPro Errors

These are typical Xbase errors that are not produced by ODBC. These errors include fundamental errors such as invalid parameters, insufficient memory, and so on. To trap these errors, you can use the traditional FoxPro error handling paradigm, including ON ERROR.

ODBC Errors

These are errors returned from the ODBC Application Programming Interface (API). Any error returned from the ODBC API is recognized by Visual FoxPro as an error outside of the scope of the internal Visual FoxPro operation. An example of this is when an SQL function called within a Visual FoxPro application returns a -1 indicating that the function failed. In this case, the value returned by the SQL function indicates failure and the errors are saved and made accessible by using AERROR(). The exact process is described in the following article in the Microsoft Knowledge Base:

   ARTICLE-ID: Q134721
   TITLE     : How to Handle Visual FoxPro Connectivity Errors
               w/o DBERROR()

Connectivity Warnings

These errors indicate situations where the ODBC-related function is completed, but the user is warned that an exception occurred. For example, some ODBC driver parameters were not set, conversion errors occurred while fetching data, the user canceled the function, multiple updates were produced by a single view row due to a non-unique key, and so on.

Warnings bring up simple alert windows that you can disable by setting the DispWarning connection property to false (.F.). You can use the SQLSETPROP() function to set the DispWarning Property.

These warnings are saved and are accessible by using AERROR(). The exact process is described in the following article in the Microsoft Knowledge Base:

   ARTICLE-ID: Q134721
   TITLE     : How to Handle Visual FoxPro Connectivity Errors
               w/o DBERROR()

In this case, you can't use an ON ERROR routine.