Database.TokyoCabinet.BDB

Contents

Basic API (tokyocabinet.idl compliant)

Description

Interface to B+ tree based DBM. See also, http://tokyocabinet.sourceforge.net/spex-en.html#tcbdbapi for details

Synopsis

Documentation

Example

    import Control.Monad
    import Database.TokyoCabinet.BDB
    import qualified Database.TokyoCabinet.BDB.Cursor as C

  
    main :: IO ()
    main =
        do bdb <- new
           -- open the database
           open bdb "casket.tcb" [OWRITER, OCREAT] >>= err bdb
           -- store records
           puts bdb [ ("foo", "hop"), ("bar", "step"), ("baz", "jump") ] >>=
                    err bdb . (all id)
           -- retrieve records
           get bdb "foo" >>= maybe (error "something goes wrong") putStrLn
           -- traverse records
           cur <- C.new bdb
           C.first cur >>= err bdb
           iter cur >>= putStrLn . show
           -- close the database
           close bdb >>= err bdb
        where
          puts :: BDB -> [(String, String)] -> IO [Bool]
          puts bdb = mapM (uncurry $ put bdb)

          err :: BDB -> Bool -> IO ()
          err bdb = flip unless $ ecode bdb >>= error . show

  
          iter :: C.BDBCUR -> IO [(String, String)]
          iter cur = do
            [key, value] <- sequence [C.key cur, C.val cur]
            case (key, value) of
              (Just k, Just v) -> C.next cur >> iter cur >>= return . ((k,v):)
              _ -> return []

data BDB Source

Instances

TCDB BDB

data ECODE Source

Represents error

Constructors

ESUCCESS	success
ETHREAD	threading error
EINVALID	invalid operation
ENOFILE	file not found
ENOPERM	no permission
EMETA	invalid meta data
ERHEAD	invalid record header
EOPEN	open error
ECLOSE	close error
ETRUNC	trunc error
ESYNC	sync error
ESTAT	stat error
ESEEK	seek error
EREAD	read error
EWRITE	write error
EMMAP	mmap error
ELOCK	lock error
EUNLINK	unlink error
ERENAME	rename error
EMKDIR	mkdir error
ERMDIR	rmdir error
EKEEP	existing record
ENOREC	no record found
EMISC	miscellaneous error

Instances

Eq ECODE
Ord ECODE
Show ECODE

data OpenMode Source

Constructors

OREADER
OWRITER
OCREAT
OTRUNC
ONOLCK
OLCKNB
OTSYNC

Instances

Eq OpenMode
Ord OpenMode
Show OpenMode

data TuningOption Source

Constructors

TLARGE
TDEFLATE
TBZIP
TTCBS
TEXCODEC

Instances

Eq TuningOption
Ord TuningOption
Show TuningOption

data CMP Source

Constructors

CMPLEXICAL
CMPDECIMAL
CMPINT32
CMPINT64
CMP (ByteString -> ByteString -> Ordering)

Basic API (tokyocabinet.idl compliant)

new :: IO BDB Source

Create a B+ tree database object.

delete :: BDB -> IO ()Source

Free BDB resource forcibly. BDB is kept by ForeignPtr, so Haskell runtime GC cleans up memory for almost situation. Most always, you don't need to call this. After call this, you must not touch BDB object. Its behavior is undefined.

ecode :: BDB -> IO ECODE Source

Return the last happened error code.

errmsg :: ECODE -> String Source

Convert error code to message string.

tune Source

Arguments

:: BDB	BDB object
-> Int32	the number of members in each leaf page.
-> Int32	the number of members in each non-leaf page.
-> Int64	the number of elements of the bucket array.
-> Int8	the size of record alignment by power of 2.
-> Int8	the maximum number of elements of the free block pool by power of 2.
-> [TuningOption]	tuning options
-> IO Bool	if successful, the return value is True.

Set the tuning parameters.

setcache Source

Arguments

:: BDB	BDB object
-> Int32	the maximum number of leaf nodes to be cached.
-> Int32	the maximum number of non-leaf nodes to be cached.
-> IO Bool	if successful, the return value is True.

Set the caching parameters.

setxmsiz :: BDB -> Int64 -> IO Bool Source

Set the size of extra mapped memory.

setcmpfunc :: BDB -> CMP -> IO Bool Source

Set the custom comparison function of a B+ tree database object.

open :: BDB -> String -> [OpenMode] -> IO Bool Source

Open BDB database file.

close :: BDB -> IO Bool Source

Close the database file.

put :: (Storable k, Storable v) => BDB -> k -> v -> IO Bool Source

Stora a record (key-value pair) on BDB. Key and value type must be instance of Storable class. Usually, we can use String, ByteString for key, String, ByteString, Int, Double for value.

putkeep :: (Storable k, Storable v) => BDB -> k -> v -> IO Bool Source

Store a new record. If a record with the same key exists in the database, this function has no effect.

putcat :: (Storable k, Storable v) => BDB -> k -> v -> IO Bool Source

Concatenate a value at the end of the existing record.

putdup :: (Storable k, Storable v) => BDB -> k -> v -> IO Bool Source

Store a record with allowing duplication of keys.

putlist :: (Storable k, Storable v, Sequence q) => BDB -> k -> q v -> IO Bool Source

Store records with allowing duplication of keys.

out :: Storable k => BDB -> k -> IO Bool Source

Delete a record. If the key of duplicated records is specified, the first one is deleted.

outlist :: Storable k => BDB -> k -> IO Bool Source

Delete records. If the key of duplicated records is specified, all of them are deleted.

get :: (Storable k, Storable v) => BDB -> k -> IO (Maybe v)Source

Return the value of record. If the key of duplicated records is specified, the first one is returned.

getlist :: (Storable k, Storable v, Sequence q) => BDB -> k -> IO (q v)Source

Retrieve records.

vnum :: Storable k => BDB -> k -> IO (Maybe Int)Source

Return the number of records corresponding to a key.

vsiz :: Storable k => BDB -> k -> IO (Maybe Int)Source

Return the size of the value of a record. If the key of duplicated records is specified, the first one is selected.

range Source

Arguments

:: (Storable k, Sequence q)
=> BDB	BDB object
-> Maybe k	the key of the beginning border. If it is Nothing, the first record in the database is specified.
-> Bool	whether the beginning border is inclusive or not.
-> Maybe k	the key of the ending border. If it is Nothing, the last record is specified.
-> Bool	whether the ending border is inclusive or not.
-> Int	the maximum number of keys to be fetched. If it is negative value, no limit is specified.
-> IO (q k)	keys in the specified range.

Return list of keys in the specified range.

fwmkeys Source

Arguments

:: (Storable k1, Storable k2, Sequence q)
=> BDB	BDB object
-> k1	search string
-> Int	the maximum number of keys to be fetched. If it is negative value, no limit is specified.
-> IO (q k2)	keys matches specified string (in forward matching).

Return list of forward matched keys.

addint Source

Arguments

:: Storable k
=> BDB	BDB object.
-> k	Key.
-> Int	Amount of increment.
-> IO (Maybe Int)	If successful, a new value is returned.

Increment the corresponding value. (The value specified by a key is treated as integer.)

adddouble Source

Arguments

:: Storable k
=> BDB	BDB object.
-> k	Key.
-> Double	Amount of increment.
-> IO (Maybe Double)	If successful, a new value is returned.

Increment the corresponding value. (The value specified by a key is treated as double.)

sync :: BDB -> IO Bool Source

Synchronize updated contents of a database object with the file and the device.

optimize Source

Arguments

:: BDB
-> Int32	the number of members in each leaf page.
-> Int32	the number of members in each non-leaf page.
-> Int64	the number of elements of the bucket array.
-> Int8	the size of record alignment by power of 2.
-> Int8	the maximum number of elements of the free block pool by power of 2.
-> [TuningOption]	tuning options
-> IO Bool	if successful, the return value is True.

Optimize the file of a B+ tree database object.

vanish :: BDB -> IO Bool Source

Delete all records.

copy :: BDB -> String -> IO Bool Source

Copy the database file.

tranbegin :: BDB -> IO Bool Source

Begin the transaction.

trancommit :: BDB -> IO Bool Source

Commit the transaction.

tranabort :: BDB -> IO Bool Source

Abort the transaction.

path :: BDB -> IO (Maybe String)Source

Return the file path of currentry opened database.

rnum :: BDB -> IO Word64 Source

Return the number of records in the database.

fsiz :: BDB -> IO Word64 Source

Return the size of the database file.