20.1.6 Customizing Error Message Display

Use an Error Handling Function to customize how users see errors raised from database constraints, trigger exceptions, or the APEX engine.

• Studying Default Error Message Behavior
  Review default error messages to see why an Error Handling Function can improve what users see.
• Specifying an Error Handling Function
  Define an Error Handling Function to rewrite server-side errors before APEX reports them.
• Examining Error Handling Function Code
  Examine an Error Handling Function that logs internal errors and replaces constraint errors with friendlier messages.
• Logging Error Info for Troubleshooting
  Log error details in a separate transaction so troubleshooting data survives the rollback.
• Experiencing Custom Error Handling
  Test custom error handling with constraint violations, database exceptions, and logged internal errors.