MigsLab The ARX specification
06 Errors
Every error an implementation raises is an **ARX exception** with a stable **code**: the same number and name in every provider and every language. The message starts with both (`ARX3001 UniqueViolation: …`). The **category** is the code's thousands digit. A provider keeps the database's own error on the exception (its native code, and the driver's error as the inner exception) but never puts values into its own messages.
| Category | Thousands | Meaning |
|---|---|---|
| Validation | 1 | Refused before the database: invalid input, a misused transaction or scope, a suspected injection |
| NotFound | 2 | The record a call needed isn't there, there are several, or it changed since it was read (ARX2004) |
| Constraint | 3 | The database refused the data: unique key, foreign key, not null, check, an error a routine raised |
| Data | 4 | A value the column can't hold |
| Schema | 5 | A table or column that doesn't exist, or doesn't match the catalog |
| Permission | 6 | The database user may not do it |
| Transient | 7 | Retrying may succeed: deadlock, serialization failure, timeout, throttling, a lost connection |
| NotSupported | 8 | The provider can't do it (chapter 08) |
| Provider | 9 | Anything else the database said |
Retry only when IsTransient is true: every Transient code is, and a provider may mark another error transient
when its database says so (DynamoDB's transaction conflicts). Every code, with its category and transient default, is
in vectors/error-codes.json; an implementation must have exactly these codes.
Language-specific exception types group the categories: in .NET ArxValidationException (1), ArxDatabaseException
(2–7, 9) and ArxNotSupportedException (8), all ArxException.