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definition:
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unique2 :: (Eq a, Eq b, Read a, Read b, Show a, Show b) =>
(Key -> (a,b) -> Dynamic) -> a -> b -> Transaction ()
unique2 entrypred k1 k2 =
getDB (allDBInfos entrypred) |>>= \is ->
if null (filter (== (k1,k2)) is)
then doneT
else errorT (TError UniqueError "relationship 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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-- Uniqueness of a combination of two attributes.
-- Check whether this combination already exists.
-- If it exists, a transaction error is generated, otherwise everything is ok.
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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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unique2
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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.Eq a, Prelude.Eq b, Prelude.Read a, Prelude.Read b, Prelude.Show a, Prelude.Show b) => (Prelude.Int
-> (a, b) -> Database.KeyDatabaseSQLite.Dynamic) -> a -> 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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