| Safe Haskell | Trustworthy |
|---|---|
| Language | Haskell2010 |
Database.LMDB.Simple.DBRef
Description
- data DBRef mode a
- newDBRef :: Serialise k => Environment mode -> Database k a -> k -> IO (DBRef mode a)
- readDBRef :: Serialise a => DBRef mode a -> IO (Maybe a)
- writeDBRef :: Serialise a => DBRef ReadWrite a -> Maybe a -> IO ()
- modifyDBRef_ :: Serialise a => DBRef ReadWrite a -> (Maybe a -> Maybe a) -> IO ()
- modifyDBRef :: Serialise a => DBRef ReadWrite a -> (Maybe a -> (Maybe a, b)) -> IO b
Documentation
A DBRef is a reference to a particular key within an LMDB database. It
may be empty (Nothing) if the key does not currently exist in the
database, or it may contain a Just value corresponding to the key.
A DBRef may be ReadWrite or ReadOnly, depending on the environment
within which it is created. Note that ReadOnly does not imply that the
contained value will not change, since the LMDB database could be modified
externally.
newDBRef :: Serialise k => Environment mode -> Database k a -> k -> IO (DBRef mode a) Source #
Create a new DBRef for the given key and database within the given
environment.
writeDBRef :: Serialise a => DBRef ReadWrite a -> Maybe a -> IO () Source #
Write a new value into a DBRef.