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89 lines
2.6 KiB
Haskell
89 lines
2.6 KiB
Haskell
-- |
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-- An API for retrieval of multiple results.
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-- Can be used to handle:
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--
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-- * A single result,
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--
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-- * Individual results of a multi-statement query
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-- with the help of "Applicative" and "Monad",
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--
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-- * Row-by-row fetching.
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module Hasql.Private.Errors where
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import Hasql.Private.Prelude
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-- |
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-- An error during the execution of a query.
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-- Comes packed with the query template and a textual representation of the provided params.
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data QueryError
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= QueryError ByteString [Text] CommandError
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deriving (Show, Eq, Typeable)
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instance Exception QueryError
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-- |
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-- An error of some command in the session.
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data CommandError
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= -- |
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-- An error on the client-side,
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-- with a message generated by the \"libpq\" library.
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-- Usually indicates problems with connection.
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ClientError (Maybe ByteString)
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| -- |
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-- Some error with a command result.
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ResultError ResultError
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deriving (Show, Eq)
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-- |
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-- An error with a command result.
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data ResultError
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= -- |
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-- An error reported by the DB.
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-- Consists of the following: Code, message, details, hint.
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--
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-- * __Code__.
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-- The SQLSTATE code for the error.
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-- It's recommended to use
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-- <http://hackage.haskell.org/package/postgresql-error-codes the "postgresql-error-codes" package>
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-- to work with those.
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--
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-- * __Message__.
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-- The primary human-readable error message (typically one line). Always present.
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--
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-- * __Details__.
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-- An optional secondary error message carrying more detail about the problem.
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-- Might run to multiple lines.
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--
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-- * __Hint__.
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-- An optional suggestion on what to do about the problem.
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-- This is intended to differ from detail in that it offers advice (potentially inappropriate)
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-- rather than hard facts.
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-- Might run to multiple lines.
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ServerError ByteString ByteString (Maybe ByteString) (Maybe ByteString)
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| -- |
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-- The database returned an unexpected result.
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-- Indicates an improper statement or a schema mismatch.
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UnexpectedResult Text
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-- An error of the row reader, preceded by the indexes of the row and column.
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RowError Int Int RowError
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-- An unexpected amount of rows.
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UnexpectedAmountOfRows Int
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deriving (Show, Eq)
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-- |
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-- An error during the decoding of a specific row.
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data RowError
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= -- |
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-- Appears on the attempt to parse more columns than there are in the result.
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EndOfInput
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-- Appears on the attempt to parse a @NULL@ as some value.
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UnexpectedNull
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-- Appears when a wrong value parser is used.
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-- Comes with the error details.
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ValueError Text
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deriving (Show, Eq)
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