CurryInfo: ertools-3.0.0 / Database.ERD.Generic.unique
definition: 
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unique :: (Read t, Show t, Eq a, Show a) =>
String -> (Key -> t -> Dynamic) -> (Key -> t -> en) -> (en -> a) -> a
-> Transaction ()
unique ename entrypred info2entry selector attrval =
getDB (allDBKeyInfos entrypred) |>>= \kis ->
if null (filter (\e -> selector e == attrval)
(map (\(k,i) -> info2entry k i) kis))
then doneT
else errorT (TError UniqueError
(ename++" entry for unique attribute "
++show attrval++" 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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documentation:
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Test whether an attribute value does not yet exist |
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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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unique |
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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 -> c) -> c -> 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 |