Error Messages
SourcePro DB handles errors differently depending upon how they are generated. The following sections describe error messages used with the DB Access Module for ODBC.
Errors and ODBC Conformance
Because the DB Interface Module does not simulate behavior that is not provided in the ODBC API and ODBC SQL grammar, certain functions of the DB Interface Module are reported as errors using the error code RWDBStatus::notSupported. For example, there is no ODBC grammar that generally supports the idea of an RWDBDatabase::createProcedure() function, so it is reported as “not supported.”
There is a much broader range of possible errors that depend entirely on the underlying ODBC driver in use. Errors of this sort are most likely to occur during the execution of advanced SQL via a call to SQLExecute(). These errors are reported using the error code RWDBStatus::serverError.
SourcePro DB makes no attempt to mitigate against such errors, but when an error does occur, information is transferred to DB Interface Module objects as described below.
Errors and RWDBStatus
When an error or warning is generated by an Access Module call to the ODBC API, information about the event is retrieved via a call to
SQLGetDiagRec() and transferred to an
RWDBStatus. This
RWDBStatus object is passed as a parameter to the installed error handler. The following list provides the format that
RWDBStatus uses to describe events reported by the ODBC driver:
• errorCode: RWDBStatus::serverError if an error occurred, or RWDBStatus::ok if a warning is being generated, or RWDBStatus::notConnected if a communication error occurred indicated by a SQLSTATE code of 08XXX; for example, "08001"
• message: "SQL call failed" if an error occurred, or "Success with info" if a warning is being generated
• vendorMessage1: the SQLSTATE code; for example, "21S01"
• vendorMessage2: the diagnostic message; for example, "Driver not capable"
• vendorError1: the native error code
• vendorError2: the SQLRETURN code from the SQL function that failed
An application can use the mapping shown previously to write an error handler that reports errors on cerr and issues warnings on clog. For example:
void myErrorHandler(const RWDBStatus& stat)
{
if (stat.errorCode() != RWDBStatus::ok) // Errors
cerr << stat.vendorMessage2();
else // Warnings
clog << stat.vendorMessage2();
}
All errors associated with the status will be reported.