diff --git a/lib/errors.py b/lib/errors.py
index 492d5aac..99ab0b04 100644
--- a/lib/errors.py
+++ b/lib/errors.py
@@ -21,1519 +21,1294 @@ def lookup(code):
 _by_sqlstate = {}
 
 
+def for_sqlstate(state):
+    def for_sqlstate_(cls):
+        _by_sqlstate[state] = cls
+        return cls
+    return for_sqlstate_
+
+
 # autogenerated data: do not edit below this point.
 
 
 # Class 02 - No Data (this is also a warning class per the SQL standard)
 
 
+@for_sqlstate('02000')
 class NoData(DatabaseError):
     pass
 
-_by_sqlstate['02000'] = NoData
-
 
+@for_sqlstate('02001')
 class NoAdditionalDynamicResultSetsReturned(DatabaseError):
     pass
 
-_by_sqlstate['02001'] = NoAdditionalDynamicResultSetsReturned
-
 
 # Class 03 - SQL Statement Not Yet Complete
 
 
+@for_sqlstate('03000')
 class SqlStatementNotYetComplete(DatabaseError):
     pass
 
-_by_sqlstate['03000'] = SqlStatementNotYetComplete
-
 
 # Class 08 - Connection Exception
 
 
+@for_sqlstate('08000')
 class ConnectionException(DatabaseError):
     pass
 
-_by_sqlstate['08000'] = ConnectionException
-
 
+@for_sqlstate('08001')
 class SqlclientUnableToEstablishSqlconnection(DatabaseError):
     pass
 
-_by_sqlstate['08001'] = SqlclientUnableToEstablishSqlconnection
-
 
+@for_sqlstate('08003')
 class ConnectionDoesNotExist(DatabaseError):
     pass
 
-_by_sqlstate['08003'] = ConnectionDoesNotExist
-
 
+@for_sqlstate('08004')
 class SqlserverRejectedEstablishmentOfSqlconnection(DatabaseError):
     pass
 
-_by_sqlstate['08004'] = SqlserverRejectedEstablishmentOfSqlconnection
-
 
+@for_sqlstate('08006')
 class ConnectionFailure(DatabaseError):
     pass
 
-_by_sqlstate['08006'] = ConnectionFailure
-
 
+@for_sqlstate('08007')
 class TransactionResolutionUnknown(DatabaseError):
     pass
 
-_by_sqlstate['08007'] = TransactionResolutionUnknown
-
 
+@for_sqlstate('08P01')
 class ProtocolViolation(DatabaseError):
     pass
 
-_by_sqlstate['08P01'] = ProtocolViolation
-
 
 # Class 09 - Triggered Action Exception
 
 
+@for_sqlstate('09000')
 class TriggeredActionException(DatabaseError):
     pass
 
-_by_sqlstate['09000'] = TriggeredActionException
-
 
 # Class 0A - Feature Not Supported
 
 
+@for_sqlstate('0A000')
 class FeatureNotSupported(NotSupportedError):
     pass
 
-_by_sqlstate['0A000'] = FeatureNotSupported
-
 
 # Class 0B - Invalid Transaction Initiation
 
 
+@for_sqlstate('0B000')
 class InvalidTransactionInitiation(DatabaseError):
     pass
 
-_by_sqlstate['0B000'] = InvalidTransactionInitiation
-
 
 # Class 0F - Locator Exception
 
 
+@for_sqlstate('0F000')
 class LocatorException(DatabaseError):
     pass
 
-_by_sqlstate['0F000'] = LocatorException
-
 
+@for_sqlstate('0F001')
 class InvalidLocatorSpecification(DatabaseError):
     pass
 
-_by_sqlstate['0F001'] = InvalidLocatorSpecification
-
 
 # Class 0L - Invalid Grantor
 
 
+@for_sqlstate('0L000')
 class InvalidGrantor(DatabaseError):
     pass
 
-_by_sqlstate['0L000'] = InvalidGrantor
-
 
+@for_sqlstate('0LP01')
 class InvalidGrantOperation(DatabaseError):
     pass
 
-_by_sqlstate['0LP01'] = InvalidGrantOperation
-
 
 # Class 0P - Invalid Role Specification
 
 
+@for_sqlstate('0P000')
 class InvalidRoleSpecification(DatabaseError):
     pass
 
-_by_sqlstate['0P000'] = InvalidRoleSpecification
-
 
 # Class 0Z - Diagnostics Exception
 
 
+@for_sqlstate('0Z000')
 class DiagnosticsException(DatabaseError):
     pass
 
-_by_sqlstate['0Z000'] = DiagnosticsException
-
 
+@for_sqlstate('0Z002')
 class StackedDiagnosticsAccessedWithoutActiveHandler(DatabaseError):
     pass
 
-_by_sqlstate['0Z002'] = StackedDiagnosticsAccessedWithoutActiveHandler
-
 
 # Class 20 - Case Not Found
 
 
+@for_sqlstate('20000')
 class CaseNotFound(ProgrammingError):
     pass
 
-_by_sqlstate['20000'] = CaseNotFound
-
 
 # Class 21 - Cardinality Violation
 
 
+@for_sqlstate('21000')
 class CardinalityViolation(ProgrammingError):
     pass
 
-_by_sqlstate['21000'] = CardinalityViolation
-
 
 # Class 22 - Data Exception
 
 
+@for_sqlstate('22000')
 class DataException(DataError):
     pass
 
-_by_sqlstate['22000'] = DataException
-
 
+@for_sqlstate('22001')
 class StringDataRightTruncation(DataError):
     pass
 
-_by_sqlstate['22001'] = StringDataRightTruncation
-
 
+@for_sqlstate('22002')
 class NullValueNoIndicatorParameter(DataError):
     pass
 
-_by_sqlstate['22002'] = NullValueNoIndicatorParameter
-
 
+@for_sqlstate('22003')
 class NumericValueOutOfRange(DataError):
     pass
 
-_by_sqlstate['22003'] = NumericValueOutOfRange
-
 
+@for_sqlstate('22004')
 class NullValueNotAllowed(DataError):
     pass
 
-_by_sqlstate['22004'] = NullValueNotAllowed
-
 
+@for_sqlstate('22005')
 class ErrorInAssignment(DataError):
     pass
 
-_by_sqlstate['22005'] = ErrorInAssignment
-
 
+@for_sqlstate('22007')
 class InvalidDatetimeFormat(DataError):
     pass
 
-_by_sqlstate['22007'] = InvalidDatetimeFormat
-
 
+@for_sqlstate('22008')
 class DatetimeFieldOverflow(DataError):
     pass
 
-_by_sqlstate['22008'] = DatetimeFieldOverflow
-
 
+@for_sqlstate('22009')
 class InvalidTimeZoneDisplacementValue(DataError):
     pass
 
-_by_sqlstate['22009'] = InvalidTimeZoneDisplacementValue
-
 
+@for_sqlstate('2200B')
 class EscapeCharacterConflict(DataError):
     pass
 
-_by_sqlstate['2200B'] = EscapeCharacterConflict
-
 
+@for_sqlstate('2200C')
 class InvalidUseOfEscapeCharacter(DataError):
     pass
 
-_by_sqlstate['2200C'] = InvalidUseOfEscapeCharacter
-
 
+@for_sqlstate('2200D')
 class InvalidEscapeOctet(DataError):
     pass
 
-_by_sqlstate['2200D'] = InvalidEscapeOctet
-
 
+@for_sqlstate('2200F')
 class ZeroLengthCharacterString(DataError):
     pass
 
-_by_sqlstate['2200F'] = ZeroLengthCharacterString
-
 
+@for_sqlstate('2200G')
 class MostSpecificTypeMismatch(DataError):
     pass
 
-_by_sqlstate['2200G'] = MostSpecificTypeMismatch
-
 
+@for_sqlstate('2200H')
 class SequenceGeneratorLimitExceeded(DataError):
     pass
 
-_by_sqlstate['2200H'] = SequenceGeneratorLimitExceeded
-
 
+@for_sqlstate('2200L')
 class NotAnXmlDocument(DataError):
     pass
 
-_by_sqlstate['2200L'] = NotAnXmlDocument
-
 
+@for_sqlstate('2200M')
 class InvalidXmlDocument(DataError):
     pass
 
-_by_sqlstate['2200M'] = InvalidXmlDocument
-
 
+@for_sqlstate('2200N')
 class InvalidXmlContent(DataError):
     pass
 
-_by_sqlstate['2200N'] = InvalidXmlContent
-
 
+@for_sqlstate('2200S')
 class InvalidXmlComment(DataError):
     pass
 
-_by_sqlstate['2200S'] = InvalidXmlComment
-
 
+@for_sqlstate('2200T')
 class InvalidXmlProcessingInstruction(DataError):
     pass
 
-_by_sqlstate['2200T'] = InvalidXmlProcessingInstruction
-
 
+@for_sqlstate('22010')
 class InvalidIndicatorParameterValue(DataError):
     pass
 
-_by_sqlstate['22010'] = InvalidIndicatorParameterValue
-
 
+@for_sqlstate('22011')
 class SubstringError(DataError):
     pass
 
-_by_sqlstate['22011'] = SubstringError
-
 
+@for_sqlstate('22012')
 class DivisionByZero(DataError):
     pass
 
-_by_sqlstate['22012'] = DivisionByZero
-
 
+@for_sqlstate('22013')
 class InvalidPrecedingOrFollowingSize(DataError):
     pass
 
-_by_sqlstate['22013'] = InvalidPrecedingOrFollowingSize
-
 
+@for_sqlstate('22014')
 class InvalidArgumentForNtileFunction(DataError):
     pass
 
-_by_sqlstate['22014'] = InvalidArgumentForNtileFunction
-
 
+@for_sqlstate('22015')
 class IntervalFieldOverflow(DataError):
     pass
 
-_by_sqlstate['22015'] = IntervalFieldOverflow
-
 
+@for_sqlstate('22016')
 class InvalidArgumentForNthValueFunction(DataError):
     pass
 
-_by_sqlstate['22016'] = InvalidArgumentForNthValueFunction
-
 
+@for_sqlstate('22018')
 class InvalidCharacterValueForCast(DataError):
     pass
 
-_by_sqlstate['22018'] = InvalidCharacterValueForCast
-
 
+@for_sqlstate('22019')
 class InvalidEscapeCharacter(DataError):
     pass
 
-_by_sqlstate['22019'] = InvalidEscapeCharacter
-
 
+@for_sqlstate('2201B')
 class InvalidRegularExpression(DataError):
     pass
 
-_by_sqlstate['2201B'] = InvalidRegularExpression
-
 
+@for_sqlstate('2201E')
 class InvalidArgumentForLogarithm(DataError):
     pass
 
-_by_sqlstate['2201E'] = InvalidArgumentForLogarithm
-
 
+@for_sqlstate('2201F')
 class InvalidArgumentForPowerFunction(DataError):
     pass
 
-_by_sqlstate['2201F'] = InvalidArgumentForPowerFunction
-
 
+@for_sqlstate('2201G')
 class InvalidArgumentForWidthBucketFunction(DataError):
     pass
 
-_by_sqlstate['2201G'] = InvalidArgumentForWidthBucketFunction
-
 
+@for_sqlstate('2201W')
 class InvalidRowCountInLimitClause(DataError):
     pass
 
-_by_sqlstate['2201W'] = InvalidRowCountInLimitClause
-
 
+@for_sqlstate('2201X')
 class InvalidRowCountInResultOffsetClause(DataError):
     pass
 
-_by_sqlstate['2201X'] = InvalidRowCountInResultOffsetClause
-
 
+@for_sqlstate('22021')
 class CharacterNotInRepertoire(DataError):
     pass
 
-_by_sqlstate['22021'] = CharacterNotInRepertoire
-
 
+@for_sqlstate('22022')
 class IndicatorOverflow(DataError):
     pass
 
-_by_sqlstate['22022'] = IndicatorOverflow
-
 
+@for_sqlstate('22023')
 class InvalidParameterValue(DataError):
     pass
 
-_by_sqlstate['22023'] = InvalidParameterValue
-
 
+@for_sqlstate('22024')
 class UnterminatedCString(DataError):
     pass
 
-_by_sqlstate['22024'] = UnterminatedCString
-
 
+@for_sqlstate('22025')
 class InvalidEscapeSequence(DataError):
     pass
 
-_by_sqlstate['22025'] = InvalidEscapeSequence
-
 
+@for_sqlstate('22026')
 class StringDataLengthMismatch(DataError):
     pass
 
-_by_sqlstate['22026'] = StringDataLengthMismatch
-
 
+@for_sqlstate('22027')
 class TrimError(DataError):
     pass
 
-_by_sqlstate['22027'] = TrimError
-
 
+@for_sqlstate('2202E')
 class ArraySubscriptError(DataError):
     pass
 
-_by_sqlstate['2202E'] = ArraySubscriptError
-
 
+@for_sqlstate('2202G')
 class InvalidTablesampleRepeat(DataError):
     pass
 
-_by_sqlstate['2202G'] = InvalidTablesampleRepeat
-
 
+@for_sqlstate('2202H')
 class InvalidTablesampleArgument(DataError):
     pass
 
-_by_sqlstate['2202H'] = InvalidTablesampleArgument
-
 
+@for_sqlstate('22P01')
 class FloatingPointException(DataError):
     pass
 
-_by_sqlstate['22P01'] = FloatingPointException
-
 
+@for_sqlstate('22P02')
 class InvalidTextRepresentation(DataError):
     pass
 
-_by_sqlstate['22P02'] = InvalidTextRepresentation
-
 
+@for_sqlstate('22P03')
 class InvalidBinaryRepresentation(DataError):
     pass
 
-_by_sqlstate['22P03'] = InvalidBinaryRepresentation
-
 
+@for_sqlstate('22P04')
 class BadCopyFileFormat(DataError):
     pass
 
-_by_sqlstate['22P04'] = BadCopyFileFormat
-
 
+@for_sqlstate('22P05')
 class UntranslatableCharacter(DataError):
     pass
 
-_by_sqlstate['22P05'] = UntranslatableCharacter
-
 
+@for_sqlstate('22P06')
 class NonstandardUseOfEscapeCharacter(DataError):
     pass
 
-_by_sqlstate['22P06'] = NonstandardUseOfEscapeCharacter
-
 
 # Class 23 - Integrity Constraint Violation
 
 
+@for_sqlstate('23000')
 class IntegrityConstraintViolation(IntegrityError):
     pass
 
-_by_sqlstate['23000'] = IntegrityConstraintViolation
-
 
+@for_sqlstate('23001')
 class RestrictViolation(IntegrityError):
     pass
 
-_by_sqlstate['23001'] = RestrictViolation
-
 
+@for_sqlstate('23502')
 class NotNullViolation(IntegrityError):
     pass
 
-_by_sqlstate['23502'] = NotNullViolation
-
 
+@for_sqlstate('23503')
 class ForeignKeyViolation(IntegrityError):
     pass
 
-_by_sqlstate['23503'] = ForeignKeyViolation
-
 
+@for_sqlstate('23505')
 class UniqueViolation(IntegrityError):
     pass
 
-_by_sqlstate['23505'] = UniqueViolation
-
 
+@for_sqlstate('23514')
 class CheckViolation(IntegrityError):
     pass
 
-_by_sqlstate['23514'] = CheckViolation
-
 
+@for_sqlstate('23P01')
 class ExclusionViolation(IntegrityError):
     pass
 
-_by_sqlstate['23P01'] = ExclusionViolation
-
 
 # Class 24 - Invalid Cursor State
 
 
+@for_sqlstate('24000')
 class InvalidCursorState(InternalError):
     pass
 
-_by_sqlstate['24000'] = InvalidCursorState
-
 
 # Class 25 - Invalid Transaction State
 
 
+@for_sqlstate('25000')
 class InvalidTransactionState(InternalError):
     pass
 
-_by_sqlstate['25000'] = InvalidTransactionState
-
 
+@for_sqlstate('25001')
 class ActiveSqlTransaction(InternalError):
     pass
 
-_by_sqlstate['25001'] = ActiveSqlTransaction
-
 
+@for_sqlstate('25002')
 class BranchTransactionAlreadyActive(InternalError):
     pass
 
-_by_sqlstate['25002'] = BranchTransactionAlreadyActive
-
 
+@for_sqlstate('25003')
 class InappropriateAccessModeForBranchTransaction(InternalError):
     pass
 
-_by_sqlstate['25003'] = InappropriateAccessModeForBranchTransaction
-
 
+@for_sqlstate('25004')
 class InappropriateIsolationLevelForBranchTransaction(InternalError):
     pass
 
-_by_sqlstate['25004'] = InappropriateIsolationLevelForBranchTransaction
-
 
+@for_sqlstate('25005')
 class NoActiveSqlTransactionForBranchTransaction(InternalError):
     pass
 
-_by_sqlstate['25005'] = NoActiveSqlTransactionForBranchTransaction
-
 
+@for_sqlstate('25006')
 class ReadOnlySqlTransaction(InternalError):
     pass
 
-_by_sqlstate['25006'] = ReadOnlySqlTransaction
-
 
+@for_sqlstate('25007')
 class SchemaAndDataStatementMixingNotSupported(InternalError):
     pass
 
-_by_sqlstate['25007'] = SchemaAndDataStatementMixingNotSupported
-
 
+@for_sqlstate('25008')
 class HeldCursorRequiresSameIsolationLevel(InternalError):
     pass
 
-_by_sqlstate['25008'] = HeldCursorRequiresSameIsolationLevel
-
 
+@for_sqlstate('25P01')
 class NoActiveSqlTransaction(InternalError):
     pass
 
-_by_sqlstate['25P01'] = NoActiveSqlTransaction
-
 
+@for_sqlstate('25P02')
 class InFailedSqlTransaction(InternalError):
     pass
 
-_by_sqlstate['25P02'] = InFailedSqlTransaction
-
 
+@for_sqlstate('25P03')
 class IdleInTransactionSessionTimeout(InternalError):
     pass
 
-_by_sqlstate['25P03'] = IdleInTransactionSessionTimeout
-
 
 # Class 26 - Invalid SQL Statement Name
 
 
+@for_sqlstate('26000')
 class InvalidSqlStatementName(OperationalError):
     pass
 
-_by_sqlstate['26000'] = InvalidSqlStatementName
-
 
 # Class 27 - Triggered Data Change Violation
 
 
+@for_sqlstate('27000')
 class TriggeredDataChangeViolation(OperationalError):
     pass
 
-_by_sqlstate['27000'] = TriggeredDataChangeViolation
-
 
 # Class 28 - Invalid Authorization Specification
 
 
+@for_sqlstate('28000')
 class InvalidAuthorizationSpecification(OperationalError):
     pass
 
-_by_sqlstate['28000'] = InvalidAuthorizationSpecification
-
 
+@for_sqlstate('28P01')
 class InvalidPassword(OperationalError):
     pass
 
-_by_sqlstate['28P01'] = InvalidPassword
-
 
 # Class 2B - Dependent Privilege Descriptors Still Exist
 
 
+@for_sqlstate('2B000')
 class DependentPrivilegeDescriptorsStillExist(InternalError):
     pass
 
-_by_sqlstate['2B000'] = DependentPrivilegeDescriptorsStillExist
-
 
+@for_sqlstate('2BP01')
 class DependentObjectsStillExist(InternalError):
     pass
 
-_by_sqlstate['2BP01'] = DependentObjectsStillExist
-
 
 # Class 2D - Invalid Transaction Termination
 
 
+@for_sqlstate('2D000')
 class InvalidTransactionTermination(InternalError):
     pass
 
-_by_sqlstate['2D000'] = InvalidTransactionTermination
-
 
 # Class 2F - SQL Routine Exception
 
 
+@for_sqlstate('2F000')
 class SqlRoutineException(InternalError):
     pass
 
-_by_sqlstate['2F000'] = SqlRoutineException
-
 
+@for_sqlstate('2F002')
 class ModifyingSqlDataNotPermitted(InternalError):
     pass
 
-_by_sqlstate['2F002'] = ModifyingSqlDataNotPermitted
-
 
+@for_sqlstate('2F003')
 class ProhibitedSqlStatementAttempted(InternalError):
     pass
 
-_by_sqlstate['2F003'] = ProhibitedSqlStatementAttempted
-
 
+@for_sqlstate('2F004')
 class ReadingSqlDataNotPermitted(InternalError):
     pass
 
-_by_sqlstate['2F004'] = ReadingSqlDataNotPermitted
-
 
+@for_sqlstate('2F005')
 class FunctionExecutedNoReturnStatement(InternalError):
     pass
 
-_by_sqlstate['2F005'] = FunctionExecutedNoReturnStatement
-
 
 # Class 34 - Invalid Cursor Name
 
 
+@for_sqlstate('34000')
 class InvalidCursorName(OperationalError):
     pass
 
-_by_sqlstate['34000'] = InvalidCursorName
-
 
 # Class 38 - External Routine Exception
 
 
+@for_sqlstate('38000')
 class ExternalRoutineException(InternalError):
     pass
 
-_by_sqlstate['38000'] = ExternalRoutineException
-
 
+@for_sqlstate('38001')
 class ContainingSqlNotPermitted(InternalError):
     pass
 
-_by_sqlstate['38001'] = ContainingSqlNotPermitted
 
-
-class ModifyingSqlDataNotPermitted(InternalError):
+@for_sqlstate('38002')
+class ModifyingSqlDataNotPermittedExt(InternalError):
     pass
 
-_by_sqlstate['38002'] = ModifyingSqlDataNotPermitted
 
-
-class ProhibitedSqlStatementAttempted(InternalError):
+@for_sqlstate('38003')
+class ProhibitedSqlStatementAttemptedExt(InternalError):
     pass
 
-_by_sqlstate['38003'] = ProhibitedSqlStatementAttempted
 
-
-class ReadingSqlDataNotPermitted(InternalError):
+@for_sqlstate('38004')
+class ReadingSqlDataNotPermittedExt(InternalError):
     pass
 
-_by_sqlstate['38004'] = ReadingSqlDataNotPermitted
-
 
 # Class 39 - External Routine Invocation Exception
 
 
+@for_sqlstate('39000')
 class ExternalRoutineInvocationException(InternalError):
     pass
 
-_by_sqlstate['39000'] = ExternalRoutineInvocationException
-
 
+@for_sqlstate('39001')
 class InvalidSqlstateReturned(InternalError):
     pass
 
-_by_sqlstate['39001'] = InvalidSqlstateReturned
 
-
-class NullValueNotAllowed(InternalError):
+@for_sqlstate('39004')
+class NullValueNotAllowedExt(InternalError):
     pass
 
-_by_sqlstate['39004'] = NullValueNotAllowed
-
 
+@for_sqlstate('39P01')
 class TriggerProtocolViolated(InternalError):
     pass
 
-_by_sqlstate['39P01'] = TriggerProtocolViolated
-
 
+@for_sqlstate('39P02')
 class SrfProtocolViolated(InternalError):
     pass
 
-_by_sqlstate['39P02'] = SrfProtocolViolated
-
 
+@for_sqlstate('39P03')
 class EventTriggerProtocolViolated(InternalError):
     pass
 
-_by_sqlstate['39P03'] = EventTriggerProtocolViolated
-
 
 # Class 3B - Savepoint Exception
 
 
+@for_sqlstate('3B000')
 class SavepointException(InternalError):
     pass
 
-_by_sqlstate['3B000'] = SavepointException
-
 
+@for_sqlstate('3B001')
 class InvalidSavepointSpecification(InternalError):
     pass
 
-_by_sqlstate['3B001'] = InvalidSavepointSpecification
-
 
 # Class 3D - Invalid Catalog Name
 
 
+@for_sqlstate('3D000')
 class InvalidCatalogName(ProgrammingError):
     pass
 
-_by_sqlstate['3D000'] = InvalidCatalogName
-
 
 # Class 3F - Invalid Schema Name
 
 
+@for_sqlstate('3F000')
 class InvalidSchemaName(ProgrammingError):
     pass
 
-_by_sqlstate['3F000'] = InvalidSchemaName
-
 
 # Class 40 - Transaction Rollback
 
 
+@for_sqlstate('40000')
 class TransactionRollback(TransactionRollbackError):
     pass
 
-_by_sqlstate['40000'] = TransactionRollback
-
 
+@for_sqlstate('40001')
 class SerializationFailure(TransactionRollbackError):
     pass
 
-_by_sqlstate['40001'] = SerializationFailure
-
 
+@for_sqlstate('40002')
 class TransactionIntegrityConstraintViolation(TransactionRollbackError):
     pass
 
-_by_sqlstate['40002'] = TransactionIntegrityConstraintViolation
-
 
+@for_sqlstate('40003')
 class StatementCompletionUnknown(TransactionRollbackError):
     pass
 
-_by_sqlstate['40003'] = StatementCompletionUnknown
-
 
+@for_sqlstate('40P01')
 class DeadlockDetected(TransactionRollbackError):
     pass
 
-_by_sqlstate['40P01'] = DeadlockDetected
-
 
 # Class 42 - Syntax Error or Access Rule Violation
 
 
+@for_sqlstate('42000')
 class SyntaxErrorOrAccessRuleViolation(ProgrammingError):
     pass
 
-_by_sqlstate['42000'] = SyntaxErrorOrAccessRuleViolation
-
 
+@for_sqlstate('42501')
 class InsufficientPrivilege(ProgrammingError):
     pass
 
-_by_sqlstate['42501'] = InsufficientPrivilege
-
 
+@for_sqlstate('42601')
 class SyntaxError(ProgrammingError):
     pass
 
-_by_sqlstate['42601'] = SyntaxError
-
 
+@for_sqlstate('42602')
 class InvalidName(ProgrammingError):
     pass
 
-_by_sqlstate['42602'] = InvalidName
-
 
+@for_sqlstate('42611')
 class InvalidColumnDefinition(ProgrammingError):
     pass
 
-_by_sqlstate['42611'] = InvalidColumnDefinition
-
 
+@for_sqlstate('42622')
 class NameTooLong(ProgrammingError):
     pass
 
-_by_sqlstate['42622'] = NameTooLong
-
 
+@for_sqlstate('42701')
 class DuplicateColumn(ProgrammingError):
     pass
 
-_by_sqlstate['42701'] = DuplicateColumn
-
 
+@for_sqlstate('42702')
 class AmbiguousColumn(ProgrammingError):
     pass
 
-_by_sqlstate['42702'] = AmbiguousColumn
-
 
+@for_sqlstate('42703')
 class UndefinedColumn(ProgrammingError):
     pass
 
-_by_sqlstate['42703'] = UndefinedColumn
-
 
+@for_sqlstate('42704')
 class UndefinedObject(ProgrammingError):
     pass
 
-_by_sqlstate['42704'] = UndefinedObject
-
 
+@for_sqlstate('42710')
 class DuplicateObject(ProgrammingError):
     pass
 
-_by_sqlstate['42710'] = DuplicateObject
-
 
+@for_sqlstate('42712')
 class DuplicateAlias(ProgrammingError):
     pass
 
-_by_sqlstate['42712'] = DuplicateAlias
-
 
+@for_sqlstate('42723')
 class DuplicateFunction(ProgrammingError):
     pass
 
-_by_sqlstate['42723'] = DuplicateFunction
-
 
+@for_sqlstate('42725')
 class AmbiguousFunction(ProgrammingError):
     pass
 
-_by_sqlstate['42725'] = AmbiguousFunction
-
 
+@for_sqlstate('42803')
 class GroupingError(ProgrammingError):
     pass
 
-_by_sqlstate['42803'] = GroupingError
-
 
+@for_sqlstate('42804')
 class DatatypeMismatch(ProgrammingError):
     pass
 
-_by_sqlstate['42804'] = DatatypeMismatch
-
 
+@for_sqlstate('42809')
 class WrongObjectType(ProgrammingError):
     pass
 
-_by_sqlstate['42809'] = WrongObjectType
-
 
+@for_sqlstate('42830')
 class InvalidForeignKey(ProgrammingError):
     pass
 
-_by_sqlstate['42830'] = InvalidForeignKey
-
 
+@for_sqlstate('42846')
 class CannotCoerce(ProgrammingError):
     pass
 
-_by_sqlstate['42846'] = CannotCoerce
-
 
+@for_sqlstate('42883')
 class UndefinedFunction(ProgrammingError):
     pass
 
-_by_sqlstate['42883'] = UndefinedFunction
-
 
+@for_sqlstate('428C9')
 class GeneratedAlways(ProgrammingError):
     pass
 
-_by_sqlstate['428C9'] = GeneratedAlways
-
 
+@for_sqlstate('42939')
 class ReservedName(ProgrammingError):
     pass
 
-_by_sqlstate['42939'] = ReservedName
-
 
+@for_sqlstate('42P01')
 class UndefinedTable(ProgrammingError):
     pass
 
-_by_sqlstate['42P01'] = UndefinedTable
-
 
+@for_sqlstate('42P02')
 class UndefinedParameter(ProgrammingError):
     pass
 
-_by_sqlstate['42P02'] = UndefinedParameter
-
 
+@for_sqlstate('42P03')
 class DuplicateCursor(ProgrammingError):
     pass
 
-_by_sqlstate['42P03'] = DuplicateCursor
-
 
+@for_sqlstate('42P04')
 class DuplicateDatabase(ProgrammingError):
     pass
 
-_by_sqlstate['42P04'] = DuplicateDatabase
-
 
+@for_sqlstate('42P05')
 class DuplicatePreparedStatement(ProgrammingError):
     pass
 
-_by_sqlstate['42P05'] = DuplicatePreparedStatement
-
 
+@for_sqlstate('42P06')
 class DuplicateSchema(ProgrammingError):
     pass
 
-_by_sqlstate['42P06'] = DuplicateSchema
-
 
+@for_sqlstate('42P07')
 class DuplicateTable(ProgrammingError):
     pass
 
-_by_sqlstate['42P07'] = DuplicateTable
-
 
+@for_sqlstate('42P08')
 class AmbiguousParameter(ProgrammingError):
     pass
 
-_by_sqlstate['42P08'] = AmbiguousParameter
-
 
+@for_sqlstate('42P09')
 class AmbiguousAlias(ProgrammingError):
     pass
 
-_by_sqlstate['42P09'] = AmbiguousAlias
-
 
+@for_sqlstate('42P10')
 class InvalidColumnReference(ProgrammingError):
     pass
 
-_by_sqlstate['42P10'] = InvalidColumnReference
-
 
+@for_sqlstate('42P11')
 class InvalidCursorDefinition(ProgrammingError):
     pass
 
-_by_sqlstate['42P11'] = InvalidCursorDefinition
-
 
+@for_sqlstate('42P12')
 class InvalidDatabaseDefinition(ProgrammingError):
     pass
 
-_by_sqlstate['42P12'] = InvalidDatabaseDefinition
-
 
+@for_sqlstate('42P13')
 class InvalidFunctionDefinition(ProgrammingError):
     pass
 
-_by_sqlstate['42P13'] = InvalidFunctionDefinition
-
 
+@for_sqlstate('42P14')
 class InvalidPreparedStatementDefinition(ProgrammingError):
     pass
 
-_by_sqlstate['42P14'] = InvalidPreparedStatementDefinition
-
 
+@for_sqlstate('42P15')
 class InvalidSchemaDefinition(ProgrammingError):
     pass
 
-_by_sqlstate['42P15'] = InvalidSchemaDefinition
-
 
+@for_sqlstate('42P16')
 class InvalidTableDefinition(ProgrammingError):
     pass
 
-_by_sqlstate['42P16'] = InvalidTableDefinition
-
 
+@for_sqlstate('42P17')
 class InvalidObjectDefinition(ProgrammingError):
     pass
 
-_by_sqlstate['42P17'] = InvalidObjectDefinition
-
 
+@for_sqlstate('42P18')
 class IndeterminateDatatype(ProgrammingError):
     pass
 
-_by_sqlstate['42P18'] = IndeterminateDatatype
-
 
+@for_sqlstate('42P19')
 class InvalidRecursion(ProgrammingError):
     pass
 
-_by_sqlstate['42P19'] = InvalidRecursion
-
 
+@for_sqlstate('42P20')
 class WindowingError(ProgrammingError):
     pass
 
-_by_sqlstate['42P20'] = WindowingError
-
 
+@for_sqlstate('42P21')
 class CollationMismatch(ProgrammingError):
     pass
 
-_by_sqlstate['42P21'] = CollationMismatch
-
 
+@for_sqlstate('42P22')
 class IndeterminateCollation(ProgrammingError):
     pass
 
-_by_sqlstate['42P22'] = IndeterminateCollation
-
 
 # Class 44 - WITH CHECK OPTION Violation
 
 
+@for_sqlstate('44000')
 class WithCheckOptionViolation(ProgrammingError):
     pass
 
-_by_sqlstate['44000'] = WithCheckOptionViolation
-
 
 # Class 53 - Insufficient Resources
 
 
+@for_sqlstate('53000')
 class InsufficientResources(OperationalError):
     pass
 
-_by_sqlstate['53000'] = InsufficientResources
-
 
+@for_sqlstate('53100')
 class DiskFull(OperationalError):
     pass
 
-_by_sqlstate['53100'] = DiskFull
-
 
+@for_sqlstate('53200')
 class OutOfMemory(OperationalError):
     pass
 
-_by_sqlstate['53200'] = OutOfMemory
-
 
+@for_sqlstate('53300')
 class TooManyConnections(OperationalError):
     pass
 
-_by_sqlstate['53300'] = TooManyConnections
-
 
+@for_sqlstate('53400')
 class ConfigurationLimitExceeded(OperationalError):
     pass
 
-_by_sqlstate['53400'] = ConfigurationLimitExceeded
-
 
 # Class 54 - Program Limit Exceeded
 
 
+@for_sqlstate('54000')
 class ProgramLimitExceeded(OperationalError):
     pass
 
-_by_sqlstate['54000'] = ProgramLimitExceeded
-
 
+@for_sqlstate('54001')
 class StatementTooComplex(OperationalError):
     pass
 
-_by_sqlstate['54001'] = StatementTooComplex
-
 
+@for_sqlstate('54011')
 class TooManyColumns(OperationalError):
     pass
 
-_by_sqlstate['54011'] = TooManyColumns
-
 
+@for_sqlstate('54023')
 class TooManyArguments(OperationalError):
     pass
 
-_by_sqlstate['54023'] = TooManyArguments
-
 
 # Class 55 - Object Not In Prerequisite State
 
 
+@for_sqlstate('55000')
 class ObjectNotInPrerequisiteState(OperationalError):
     pass
 
-_by_sqlstate['55000'] = ObjectNotInPrerequisiteState
-
 
+@for_sqlstate('55006')
 class ObjectInUse(OperationalError):
     pass
 
-_by_sqlstate['55006'] = ObjectInUse
-
 
+@for_sqlstate('55P02')
 class CantChangeRuntimeParam(OperationalError):
     pass
 
-_by_sqlstate['55P02'] = CantChangeRuntimeParam
-
 
+@for_sqlstate('55P03')
 class LockNotAvailable(OperationalError):
     pass
 
-_by_sqlstate['55P03'] = LockNotAvailable
-
 
 # Class 57 - Operator Intervention
 
 
+@for_sqlstate('57000')
 class OperatorIntervention(OperationalError):
     pass
 
-_by_sqlstate['57000'] = OperatorIntervention
-
 
+@for_sqlstate('57014')
 class QueryCanceled(QueryCanceledError):
     pass
 
-_by_sqlstate['57014'] = QueryCanceled
-
 
+@for_sqlstate('57P01')
 class AdminShutdown(OperationalError):
     pass
 
-_by_sqlstate['57P01'] = AdminShutdown
-
 
+@for_sqlstate('57P02')
 class CrashShutdown(OperationalError):
     pass
 
-_by_sqlstate['57P02'] = CrashShutdown
-
 
+@for_sqlstate('57P03')
 class CannotConnectNow(OperationalError):
     pass
 
-_by_sqlstate['57P03'] = CannotConnectNow
-
 
+@for_sqlstate('57P04')
 class DatabaseDropped(OperationalError):
     pass
 
-_by_sqlstate['57P04'] = DatabaseDropped
-
 
 # Class 58 - System Error (errors external to PostgreSQL itself)
 
 
+@for_sqlstate('58000')
 class SystemError(OperationalError):
     pass
 
-_by_sqlstate['58000'] = SystemError
-
 
+@for_sqlstate('58030')
 class IoError(OperationalError):
     pass
 
-_by_sqlstate['58030'] = IoError
-
 
+@for_sqlstate('58P01')
 class UndefinedFile(OperationalError):
     pass
 
-_by_sqlstate['58P01'] = UndefinedFile
-
 
+@for_sqlstate('58P02')
 class DuplicateFile(OperationalError):
     pass
 
-_by_sqlstate['58P02'] = DuplicateFile
-
 
 # Class 72 - Snapshot Failure
 
 
+@for_sqlstate('72000')
 class SnapshotTooOld(DatabaseError):
     pass
 
-_by_sqlstate['72000'] = SnapshotTooOld
-
 
 # Class F0 - Configuration File Error
 
 
+@for_sqlstate('F0000')
 class ConfigFileError(InternalError):
     pass
 
-_by_sqlstate['F0000'] = ConfigFileError
-
 
+@for_sqlstate('F0001')
 class LockFileExists(InternalError):
     pass
 
-_by_sqlstate['F0001'] = LockFileExists
-
 
 # Class HV - Foreign Data Wrapper Error (SQL/MED)
 
 
+@for_sqlstate('HV000')
 class FdwError(OperationalError):
     pass
 
-_by_sqlstate['HV000'] = FdwError
-
 
+@for_sqlstate('HV001')
 class FdwOutOfMemory(OperationalError):
     pass
 
-_by_sqlstate['HV001'] = FdwOutOfMemory
-
 
+@for_sqlstate('HV002')
 class FdwDynamicParameterValueNeeded(OperationalError):
     pass
 
-_by_sqlstate['HV002'] = FdwDynamicParameterValueNeeded
-
 
+@for_sqlstate('HV004')
 class FdwInvalidDataType(OperationalError):
     pass
 
-_by_sqlstate['HV004'] = FdwInvalidDataType
-
 
+@for_sqlstate('HV005')
 class FdwColumnNameNotFound(OperationalError):
     pass
 
-_by_sqlstate['HV005'] = FdwColumnNameNotFound
-
 
+@for_sqlstate('HV006')
 class FdwInvalidDataTypeDescriptors(OperationalError):
     pass
 
-_by_sqlstate['HV006'] = FdwInvalidDataTypeDescriptors
-
 
+@for_sqlstate('HV007')
 class FdwInvalidColumnName(OperationalError):
     pass
 
-_by_sqlstate['HV007'] = FdwInvalidColumnName
-
 
+@for_sqlstate('HV008')
 class FdwInvalidColumnNumber(OperationalError):
     pass
 
-_by_sqlstate['HV008'] = FdwInvalidColumnNumber
-
 
+@for_sqlstate('HV009')
 class FdwInvalidUseOfNullPointer(OperationalError):
     pass
 
-_by_sqlstate['HV009'] = FdwInvalidUseOfNullPointer
-
 
+@for_sqlstate('HV00A')
 class FdwInvalidStringFormat(OperationalError):
     pass
 
-_by_sqlstate['HV00A'] = FdwInvalidStringFormat
-
 
+@for_sqlstate('HV00B')
 class FdwInvalidHandle(OperationalError):
     pass
 
-_by_sqlstate['HV00B'] = FdwInvalidHandle
-
 
+@for_sqlstate('HV00C')
 class FdwInvalidOptionIndex(OperationalError):
     pass
 
-_by_sqlstate['HV00C'] = FdwInvalidOptionIndex
-
 
+@for_sqlstate('HV00D')
 class FdwInvalidOptionName(OperationalError):
     pass
 
-_by_sqlstate['HV00D'] = FdwInvalidOptionName
-
 
+@for_sqlstate('HV00J')
 class FdwOptionNameNotFound(OperationalError):
     pass
 
-_by_sqlstate['HV00J'] = FdwOptionNameNotFound
-
 
+@for_sqlstate('HV00K')
 class FdwReplyHandle(OperationalError):
     pass
 
-_by_sqlstate['HV00K'] = FdwReplyHandle
-
 
+@for_sqlstate('HV00L')
 class FdwUnableToCreateExecution(OperationalError):
     pass
 
-_by_sqlstate['HV00L'] = FdwUnableToCreateExecution
-
 
+@for_sqlstate('HV00M')
 class FdwUnableToCreateReply(OperationalError):
     pass
 
-_by_sqlstate['HV00M'] = FdwUnableToCreateReply
-
 
+@for_sqlstate('HV00N')
 class FdwUnableToEstablishConnection(OperationalError):
     pass
 
-_by_sqlstate['HV00N'] = FdwUnableToEstablishConnection
-
 
+@for_sqlstate('HV00P')
 class FdwNoSchemas(OperationalError):
     pass
 
-_by_sqlstate['HV00P'] = FdwNoSchemas
-
 
+@for_sqlstate('HV00Q')
 class FdwSchemaNotFound(OperationalError):
     pass
 
-_by_sqlstate['HV00Q'] = FdwSchemaNotFound
-
 
+@for_sqlstate('HV00R')
 class FdwTableNotFound(OperationalError):
     pass
 
-_by_sqlstate['HV00R'] = FdwTableNotFound
-
 
+@for_sqlstate('HV010')
 class FdwFunctionSequenceError(OperationalError):
     pass
 
-_by_sqlstate['HV010'] = FdwFunctionSequenceError
-
 
+@for_sqlstate('HV014')
 class FdwTooManyHandles(OperationalError):
     pass
 
-_by_sqlstate['HV014'] = FdwTooManyHandles
-
 
+@for_sqlstate('HV021')
 class FdwInconsistentDescriptorInformation(OperationalError):
     pass
 
-_by_sqlstate['HV021'] = FdwInconsistentDescriptorInformation
-
 
+@for_sqlstate('HV024')
 class FdwInvalidAttributeValue(OperationalError):
     pass
 
-_by_sqlstate['HV024'] = FdwInvalidAttributeValue
-
 
+@for_sqlstate('HV090')
 class FdwInvalidStringLengthOrBufferLength(OperationalError):
     pass
 
-_by_sqlstate['HV090'] = FdwInvalidStringLengthOrBufferLength
-
 
+@for_sqlstate('HV091')
 class FdwInvalidDescriptorFieldIdentifier(OperationalError):
     pass
 
-_by_sqlstate['HV091'] = FdwInvalidDescriptorFieldIdentifier
-
 
 # Class P0 - PL/pgSQL Error
 
 
+@for_sqlstate('P0000')
 class PlpgsqlError(InternalError):
     pass
 
-_by_sqlstate['P0000'] = PlpgsqlError
-
 
+@for_sqlstate('P0001')
 class RaiseException(InternalError):
     pass
 
-_by_sqlstate['P0001'] = RaiseException
-
 
+@for_sqlstate('P0002')
 class NoDataFound(InternalError):
     pass
 
-_by_sqlstate['P0002'] = NoDataFound
-
 
+@for_sqlstate('P0003')
 class TooManyRows(InternalError):
     pass
 
-_by_sqlstate['P0003'] = TooManyRows
-
 
+@for_sqlstate('P0004')
 class AssertFailure(InternalError):
     pass
 
-_by_sqlstate['P0004'] = AssertFailure
-
 
 # Class XX - Internal Error
 
 
-class InternalError(InternalError):
+@for_sqlstate('XX000')
+class InternalError_(InternalError):
     pass
 
-_by_sqlstate['XX000'] = InternalError
-
 
+@for_sqlstate('XX001')
 class DataCorrupted(InternalError):
     pass
 
-_by_sqlstate['XX001'] = DataCorrupted
-
 
+@for_sqlstate('XX002')
 class IndexCorrupted(InternalError):
     pass
-
-_by_sqlstate['XX002'] = IndexCorrupted
diff --git a/scripts/make_errors.py b/scripts/make_errors.py
index cdf299f6..6a59cf1a 100755
--- a/scripts/make_errors.py
+++ b/scripts/make_errors.py
@@ -114,11 +114,24 @@ def fetch_errors(versions):
 def generate_module_data(classes, errors):
     tmpl = """
 
+@for_sqlstate(%(errcode)r)
 class %(cls)s(%(base)s):
-    pass
-
-_by_sqlstate[%(errcode)r] = %(cls)s\
+    pass\
 """
+    specific = {
+        '38002': 'ModifyingSqlDataNotPermittedExt',
+        '38003': 'ProhibitedSqlStatementAttemptedExt',
+        '38004': 'ReadingSqlDataNotPermittedExt',
+        '39004': 'NullValueNotAllowedExt',
+        'XX000': 'InternalError_',
+    }
+
+    seen = set("""
+        Error Warning InterfaceError DataError DatabaseError ProgrammingError
+        IntegrityError InternalError NotSupportedError OperationalError
+        QueryCanceledError TransactionRollbackError
+        """.split())
+
     for clscode, clslabel in sorted(classes.items()):
         if clscode in ('00', '01'):
             # success and warning - never raised
@@ -127,7 +140,14 @@ _by_sqlstate[%(errcode)r] = %(cls)s\
         yield "\n\n# %s" % clslabel
 
         for errcode, errlabel in sorted(errors[clscode].items()):
-            clsname = errlabel.title().replace('_', '')
+            if errcode in specific:
+                clsname = specific[errcode]
+            else:
+                clsname = errlabel.title().replace('_', '')
+            if clsname in seen:
+                raise Exception("class already existing: %s" % clsname)
+            seen.add(clsname)
+
             yield tmpl % {
                 'cls': clsname,
                 'base': get_base_class_name(errcode),