# SQLAlchemy 0.4 Documentation

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Version: 0.4.6 Last Updated: 05/14/08 14:36:43

### module sqlalchemy.exceptions

Exceptions used with SQLAlchemy.

The base exception class is SQLAlchemyError. Exceptions which are raised as a result of DBAPI exceptions are all subclasses of DBAPIError.

### class ArgumentError(SQLAlchemyError)

Raised for all those conditions where invalid arguments are sent to constructed objects. This error generally corresponds to construction time state errors.

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### class AssertionError(SQLAlchemyError)

Corresponds to internal state being detected in an invalid state.

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### class CircularDependencyError(SQLAlchemyError)

Raised by topological sorts when a circular dependency is detected

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### class CompileError(SQLAlchemyError)

Raised when an error occurs during SQL compilation

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### class ConcurrentModificationError(SQLAlchemyError)

Raised when a concurrent modification condition is detected.

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### class DBAPIError(SQLAlchemyError)

Raised when the execution of a database operation fails.

`DBAPIError` wraps exceptions raised by the DB-API underlying the database operation. Driver-specific implementations of the standard DB-API exception types are wrapped by matching sub-types of SQLAlchemy's `DBAPIError` when possible. DB-API's `Error` type maps to `DBAPIError` in SQLAlchemy, otherwise the names are identical. Note that there is no guarantee that different DB-API implementations will raise the same exception type for any given error condition.

If the error-raising operation occured in the execution of a SQL statement, that statement and its parameters will be available on the exception object in the `statement` and `params` attributes.

The wrapped exception object is available in the `orig` attribute. Its type and properties are DB-API implementation specific.

def __init__(self, statement, params, orig, connection_invalidated=False)

Construct a new `DBAPIError`.

def instance(cls, statement, params, orig, connection_invalidated=False)
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### class DataError(DatabaseError)

Wraps a DB-API DataError.

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### class DatabaseError(DBAPIError)

Wraps a DB-API DatabaseError.

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### class DisconnectionError(SQLAlchemyError)

Raised within `Pool` when a disconnect is detected on a raw DB-API connection.

This error is consumed internally by a connection pool. It can be raised by a `PoolListener` so that the host pool forces a disconnect.

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### class FlushError(SQLAlchemyError)

Raised when an invalid condition is detected upon a `flush()`.

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### class IntegrityError(DatabaseError)

Wraps a DB-API IntegrityError.

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### class InterfaceError(DBAPIError)

Wraps a DB-API InterfaceError.

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### class InternalError(DatabaseError)

Wraps a DB-API InternalError.

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### class InvalidRequestError(SQLAlchemyError)

SQLAlchemy was asked to do something it can't do, return nonexistent data, etc.

This error generally corresponds to runtime state errors.

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### class NoReferencedTableError(InvalidRequestError)

Raised by `ForeignKey` when the referred `Table` cannot be located.

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### class NoSuchColumnError(KeyError,SQLAlchemyError)

Raised by `RowProxy` when a nonexistent column is requested from a row.

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### class NoSuchTableError(InvalidRequestError)

SQLAlchemy was asked to load a table's definition from the database, but the table doesn't exist.

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### class NotSupportedError(DatabaseError)

Wraps a DB-API NotSupportedError.

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### class OperationalError(DatabaseError)

Wraps a DB-API OperationalError.

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### class ProgrammingError(DatabaseError)

Wraps a DB-API ProgrammingError.

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### class SADeprecationWarning(DeprecationWarning)

Issued once per usage of a deprecated API.

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### class SAPendingDeprecationWarning(PendingDeprecationWarning)

Issued once per usage of a deprecated API.

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### class SAWarning(RuntimeWarning)

Issued at runtime.

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### class SQLAlchemyError(Exception)

Generic error class.

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### class TimeoutError(SQLAlchemyError)

Raised when a connection pool times out on getting a connection.

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### class UnboundExecutionError(InvalidRequestError)

SQL was attempted without a database connection to execute it on.

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### class UnmappedColumnError(InvalidRequestError)

A mapper was asked to return mapped information about a column which it does not map

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