Modulepostgresql-simple-0.7.0.0Haskell2010

Database.PostgreSQL.Simple.Errors

| Module for parsing errors from postgresql error messages. Currently only parses integrity violation errors (class 23).

Note: Success of parsing may depend on language settings.

1 type
6 values

Packagepostgresql-simple-0.7.0.0
Exports7
LanguageHaskell2010
LicenceBSD-3-Clause
SourceErrors.hs

datadata ConstraintViolation

Constructors

NotNullViolation ByteString
The field is a column name
ForeignKeyViolation ByteString ByteString
Table name and name of violated constraint
UniqueViolation ByteString
Name of violated constraint
CheckViolation ByteString ByteString
Relation name (usually table), constraint name
ExclusionViolation ByteString
Name of the exclusion violation constraint

Instances4Eq, Ord, Show, Exception

Eq ConstraintViolationDefined in postgresql-simple-0.7.0.0 · Database.PostgreSQL.Simple.Errors
Ord ConstraintViolationDefined in postgresql-simple-0.7.0.0 · Database.PostgreSQL.Simple.Errors
Show ConstraintViolationDefined in postgresql-simple-0.7.0.0 · Database.PostgreSQL.Simple.Errors
Exception ConstraintViolationDefined in postgresql-simple-0.7.0.0 · Database.PostgreSQL.Simple.Errors

valueconstraintViolation :: SqlError -> Maybe ConstraintViolation

Tries to convert SqlError to ConstrainViolation, checks sqlState and succeeds only if able to parse sqlErrorMsg.

createUser = handleJust constraintViolation handler $ execute conn ...
  where
    handler (UniqueViolation "user_login_key") = ...
    handler _ = ...

valueconstraintViolationE :: SqlError -> Maybe (SqlError, ConstraintViolation)

Like constraintViolation, but also packs original SqlError.

createUser = handleJust constraintViolationE handler $ execute conn ...
  where
    handler (_, UniqueViolation "user_login_key") = ...
    handler (e, _) = throwIO e

valuecatchViolation :: (SqlError -> ConstraintViolation -> IO a) -> IO a -> IO a

Catches SqlError, tries to convert to ConstraintViolation, re-throws on fail. Provides alternative interface to handleJust

createUser = catchViolation catcher $ execute conn ...
  where
    catcher _ (UniqueViolation "user_login_key") = ...
    catcher e _ = throwIO e

valueisSerializationError :: SqlError -> Bool

valueisNoActiveTransactionError :: SqlError -> Bool

valueisFailedTransactionError :: SqlError -> Bool