< Erlang (programming language) | TutorialsRevision as of 12:30, 22 April 2008 by imported>Chris Day
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ETS local data storage
ETS is the erlang table storage system, which provides hash storage and access functions.
ETS data is stored in a process as long as it is running.
Here is a sample of how to use some simple functions in ETS
Sample program: test_ets.erl
-module(test_ets).
-compile(export_all).
start() -> start( mouse ).
start( Animal ) ->
Kingdom = ets:new( 'magic', [] ),
% note: table is not square
populate( Kingdom, [{micky,mouse}, {mini,mouse}, {goofy}] ),
Member = ets:member( Kingdom, micky ),
io:format( " member ~w ~n ", [ Member ] ),
show_next_key( Kingdom, micky ),
find_animal( Kingdom, Animal ).
show_next_key( _Kingdom, '$end_of_table' ) -> done;
show_next_key( Kingdom, Key) ->
Next = ets:next( Kingdom, Key ),
io:format( " next ~w ~n ", [ Next ] ),
show_next_key( Kingdom, Next ).
populate( _Kingdom, [] ) -> {done,start};
populate( Kingdom, [H | T] ) ->
ets:insert( Kingdom, H ),
populate( Kingdom, T ).
find_animal( Kingdom, Animal ) ->
ets:match( Kingdom, { '$1', Animal } ).
% ==============
% sample output
% ==============
% 53> test_ets:start().
% member true
% next mini
% next goofy
% next '$end_of_table'
% [[mini],[micky]]