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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:
|
deterministic operation
|
|
documentation:
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-- Test whether an attribute value does not yet exist
|
|
failfree:
|
<FAILING>
|
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indeterministic:
|
referentially transparent operation
|
|
infix:
|
no fixity defined
|
|
iotype:
|
{(_,_,_,_,_,_,_,_,_) |-> _}
|
|
name:
|
unique
|
|
precedence:
|
no precedence defined
|
|
result-values:
|
_
|
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signature:
|
(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:
|
operation might suspend on free variables
|
|
terminating:
|
possibly non-terminating
|
|
totally-defined:
|
possibly non-reducible on same data term
|