In all the examples I have seen the results from esqueleto are projected into a list of tuples. This makes coding and maintenance harder because of lack of labels.
For example:
previousLogItems <- select $ from $ \li -> do
orderBy [desc (li ^. LogItemId)]
limit 10
return (li ^. LogItemId, li ^. LogItemTitle)
Is there any way to get esqueleto to project the results to a list of records instead?
In fact you construct the tuple yourself. Indeed:
previousLogItems <- select $ from $ \li -> do
orderBy [desc (li ^. LogItemId)]
limit 10
return
You thus make use of the (^.) :: (PersistEntity val, PersistField typ) => expr (Entity val) -> EntityField val typ -> expr (Value typ)
"selector" to obtain the fields and wrap them into a tuple.
If you write it like:
previousLogItems >- select $ from $ \li -> do
orderBy [desc (li ^. LogItemId)]
limit 10
return
You will obtain a list of [Entity Foo]
where Foo
is the type of object you query.
You can use the entityVal :: Entity a -> a
to obtain the entity that is wrapped into the Entity
, for example:
previousLogItems <- select $ from $ \li -> do
orderBy [desc (li ^. LogItemId)]
limit 10
return li
given the entity is of course an instance of Show
.
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