mc_worker_api¶

direct connection client:

Database = <<"test">>.
case mc_worker_api:connect([{database, Database}]) of
    {ok, Connection} ->
      ok;
    {error, Reason} ->
      error
end.

Writing¶

> Collection = <<"test">>.
> mc_worker_api:insert(Connection, Collection,
    [
     #{<<"name">> => <<"Yankees">>,
       <<"home">> => #{<<"city">> => <<"New York">>, <<"state">> => <<"NY">>},
       <<"league">> => <<"American">>},
     #{<<"name">> => <<"Mets">>,
       <<"home">> => #{<<"city">> => <<"New York">>, <<"state">> => <<"NY">>},
       <<"league">> => <<"National">>},
     #{<<"name">> => <<"Phillies">>,
       <<"home">> => #{<<"city">> => <<"Philadelphia">>, <<"state">> => <<"PA">>},
       <<"league">> => <<"National">>},
     #{<<"name">> => <<"Red Sox">>,
       <<"home">>=> #{<<"city">> => <<"Boston">>, <<"state">> => <<"MA">>},
       <<"league">> => <<"American">>}
   ]).

> mc_worker_api:delete(Connection, Collection, Selector).
如:
> Collection = <<"test">>.
> mc_worker_api:insert(Connection, Collection,
    #{
      <<"name">> => <<"Yankees">>,
      <<"home">> => #{
          <<"city">> => <<"New York">>,
          <<"state">> => <<"NY">>},
          <<"league">> => <<"American">>
      }).

Reading¶

> {ok, Cursor} = mc_worker_api:find(Connection, Collection, Selector)
> Result = mc_cursor:next(Cursor),
> mc_cursor:close(Cursor),

备注

Important! Do not forget to close cursors after using them! mc_cursor:rest closes the cursor automatically.

实例:

mc_worker_api:find_one(Connection, Collection, #{<<"key">> => <<"123">>}).

mc_worker_api:find_one(Connection, Collection,
      #{<<"key">> => <<"123">>, <<"value">> => <<"built_in">>}).

% 只读取_id和value字段
mc_worker_api:find_one(Connection, Collection, {},
      #{projector => #{<<"value">> => true}).
% 只读取_id字段
mc_worker_api:find_one(Connection, Collection, {},
    #{projector => #{<<"key">> => false, <<"value">> => false}}).

Updating¶

实例:

Command = #{<<"$set">> => #{
    <<"quantity">> => 500,
    <<"details">> => #{<<"model">> => "14Q3", <<"make">> => "xyz"},
    <<"tags">> => ["coats", "outerwear", "clothing"]
}},
mc_worker_api:update(Connection, Collection, #{<<"_id">> => 100}, Command),

% 如没有expired字段，增加新字段
Command = #{<<"$set">> => #{<<"expired">> => true}},
mc_worker_api:update(Connection, Collection, #{<<"_id">> => 100}, Command),

% 更新嵌套文档中的字段
Command = #{<<"$set">> => #{<<"details.make">> => "zzz"}},
mc_worker_api:update(Connection, Collection, #{<<"_id">> => 100}, Command),

% 数组更新
Command = #{<<"$set">> => #{
    <<"tags.1">> => "rain gear",
    <<"ratings.0.rating">> => 2
  }},
mc_worker_api:update(Connection, Collection, #{'_id' => 100}, Command),

Creating indexes¶

mc_worker_api:ensure_index(Connection, Collection, #{
    <<"key">> => #{<<"index">> => 1}
  }).  %simple
mc_worker_api:ensure_index(Connection, Collection, #{
    <<"key">> => #{<<"index">> => 1},
    <<"name">> => <<"MyI">>
  }).  %advanced
mc_worker_api:ensure_index(Connection, Collection, #{
    <<"key">> => #{<<"index">> => 1},
    <<"name">> => <<"MyI">>,
    <<"unique">> => true,
    <<"dropDups">> => true
  }).  %full