@c -*-texinfo-*-
@c This is part of the XEmacs Lisp Reference Manual.
@c Copyright (C) 1996 Ben Wing.
@c See the file lispref.texi for copying conditions.
@setfilename ../../info/databases.info
@node Databases, Processes, Range Tables, top
@chapter Databases
@cindex database

@defun databasep object
This function returns non-@code{nil} if @var{object} is a database.
@end defun

@menu
* Connecting to a Database::
* Working With a Database::
* Other Database Functions::
@end menu

@node Connecting to a Database
@section Connecting to a Database

@defun open-database file &optional type subtype access mode
This function opens database @var{file}, using database method
@var{type} and @var{subtype}, with access rights @var{access} and
permissions @var{mode}.  @var{access} can be any combination of @code{r}
@code{w} and @code{+}, for read, write, and creation flags.

@var{type} can have the value @code{'dbm} or @code{'berkeley-db} to
select the type of database file to use.  (Note:  XEmacs may not
support both of these types.)

For a @var{type} of @code{'dbm}, there are no subtypes, so
@var{subtype} should be @code{nil}.

For a @var{type} of @code{'berkeley-db}, the following subtypes are
available:  @code{'hash}, @code{'btree}, and @code{'recno}.  See the
manpages for the Berkeley DB functions for more information about these
types.
@end defun

@defun close-database database
This function closes database @var{database}.
@end defun

@defun database-live-p object
This function returns @code{t} if @var{object} is an active database, else
@code{nil}.
@end defun

@node Working With a Database
@section Working With a Database

@defun get-database key database &optional default
This function finds the value for @var{key} in @var{database}.  If there is no
corresponding value, @var{default} is returned (@code{nil} if @var{default} is
omitted).
@end defun

@defun map-database function database
This function maps @var{function} over entries in @var{database},
calling it with two args, each key and value in the database.
@end defun

@defun put-database key value database &optional replace
This function stores @var{key} and @var{value} in @var{database}.
If optional fourth arg @var{replace} is non-@code{nil}, replace any
existing entry in the database.
@end defun

@defun remove-database key database
This function removes @var{key} from @var{database}.
@end defun

@node Other Database Functions
@section Other Database Functions

@defun database-file-name database
This function returns the filename associated with @var{database}.
@end defun

@defun database-last-error &optional database
This function returns the last error associated with @var{database}.
@end defun

@defun database-subtype database
This function returns the subtype of @var{database}, if any.
@end defun

@defun database-type database
This function returns the type of @var{database}.
@end defun