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definition:
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uniqueUpdate :: (Read t, Show t, Eq a, Show a) =>
String -> (Key -> t -> Dynamic) -> (Key -> t -> en)
-> (en -> Key) -> (en -> a) -> en -> Transaction ()
uniqueUpdate ename entrypred info2entry keyf selector obj =
let oldkey = keyf obj
in
getDB (getDBInfo entrypred oldkey) |>>=
maybe (errorT (TError KeyNotExistsError
("database contains no entry for key: "++show oldkey)))
(\oldt -> getDB (allDBKeyInfos entrypred) |>>= \kis ->
let oldentry = info2entry oldkey oldt
entries = filter (\e -> selector obj == selector e)
(map (uncurry info2entry) kis)
in if null entries ||
(length entries == 1 && selector oldentry == selector obj)
then doneT
else errorT (TError UniqueError
(ename++" entry for unique attribute "
++show (selector obj)++" already exists")))
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demand:
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no demanded arguments
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deterministic:
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deterministic operation
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failfree:
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<FAILING>
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indeterministic:
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referentially transparent operation
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infix:
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no fixity defined
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iotype:
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{(_,_,_,_,_,_,_,_,_,_) |-> _}
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name:
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uniqueUpdate
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precedence:
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no precedence defined
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result-values:
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_
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signature:
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(Prelude.Read a, Prelude.Show a, Prelude.Eq c, Prelude.Show c) => String
-> (Prelude.Int -> a -> Database.KeyDatabaseSQLite.Dynamic) -> (Prelude.Int -> a
-> b) -> (b -> Prelude.Int) -> (b -> c) -> b
-> Database.KeyDatabaseSQLite.Transaction ()
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solution-complete:
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operation might suspend on free variables
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terminating:
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possibly non-terminating
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totally-defined:
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possibly non-reducible on same data term
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