Failing to Connect to an RDO Data Source

You might be unable to establish a connection for a variety of reasons, including:

• Lack of permission on the data source or network.
  
  
• Improper network connection or permissions.
  
  
• Missing or disabled data source.
  
  
• Missing or improperly installed or registered drivers. Both ODBC and network protocol drivers must be installed and registered.
  
  
• Too many connections have already been established by your application or other applications.
  
  
• The network or remote server is down or too busy to respond before the time specified by the LoginTimeout property has expired.

For example, when connecting to Microsoft SQL Server, Oracle, or other data sources, the number of simultaneous connections permitted might be limited by license agreements, resource constraints, or by database settings. Check with your server administrator if you suspect that all available connections are allocated.

In any case, your code should include comprehensive error handlers to deal with all of these and other contingencies that might apply to your situation. While some of these problems are due to setup issues, some are transitory — that is, they will correct themselves once resources are freed on the remote system or the amount of LAN or WAN traffic subsides.

Errors trapped by RDO are usually returned as generic ODBC errors that tell you very little about the root cause of the errors. However, details about the errors are saved in the rdoErrors collection. Each rdoError in the rdoErrors collection contains specific information about what went wrong. Examining the rdoError object properties can yield vital information about the specific error, including a description string, a native error number (as would be returned by SQL Server), and other values specific to the ODBC API error management scheme.

For More Information   See the Language Reference for details on the structure and properties of the rdoError object.