xotcl/library/store/Storage.xotcl
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Filename: xotcl/library/store/Storage.xotcl
Description: | Simple generic storage interface for hashtable-like (persistent) storages. There are several different existing stores, including a memory storage, a GDBM storage, a SDBM storage, and a TextFile storage. |
Date: | $Date: 2005/09/09 21:09:01 $ |
Class: Storage
Class: ClassProcs/Instprocs: close, exists, firstkey, names, nextkey, open, set, someNewChildStore, unset.
Description: | Abstract storage interface class (superclass of all storages). |
Instprocs
- open filename
Arguments: filename: database filename (or filename base, if more than one file has to be created) Description: Each storage object represents exactly one database table. The db has to be opened, before it can it used. If it is not opened all other methods return errors. Return: empty string - close
Description: Close associated database. Return: empty string - exists key
Arguments: key: Key to be searched for. Description: Search for a key whether it exists or not. Return: 1, if key exists in the database, otherwise 0 - set key
?value?
Arguments: key: Key to be set. ?value?: Optional value that might be set Description: Set or query a database key in the same way as Tcl's set functions. Return: Key value. - unset key
Arguments: key: Key to be unset. Description: Unset a database key in the same way as Tcl's unset functions. Return: empty string - names
Description: Return a list of keys in the database (functions in the same way as Tcl's array names) Return: List of keys in the db. - firstkey
Description: Start a traversal of the database, starting with any key. Return: Name of first key. - nextkey
Description: Proceed with the db traversal. Requires a firstkey before first usage, otherwise it returns an error. Return: Name of next key, if one exists. Otherwise an empty string is returned.
Procs
-
someNewChildStore
Description: Create a childStore according to a preference list depending on which storages are available. Currently the preference list has the following order: Gdbm, Sdbm and TextFile. Return: name of the created storage object.
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