使用mongdb erlang驱动程序查询返回错误的结果？ [英] Query return wrong result using mongdb erlang driver?

问题描述

当我尝试

Query = {country，<US>>}，
mongo：find（Col，{'$查询'，查询'$ orderby'，{last_seen，-1}}，投影机0,15），

Query = {country, <<"US">>}, mongo:find(Col, { '$query', Query, '$orderby', {last_seen, -1} }, Projector, 0, 15),

返回的游标不限于批量大小15再说了它将以光标返回所有结果。但是，如果我将其更改为

The cursor returned is not limited to batch size 15 any more. It will return all the results in cursor. However, if I change it to

mongo：find（Col，Query，Projector，0，15），

mongo:find(Col, Query, Projector, 0, 15),

它将返回15个大小的光标。

It will return the cursor with 15 in size.

这是一个错误还是我做错了？

Is this a bug or I did anything wrong?

推荐答案

它适用于我下面的例子

run () ->
    application:start (mongodb),
    {ok, Conn} = mongo:connect (localhost),
    {ok, Docs} = mongo:do (safe, master, Conn, test, fun() ->
        mongo:delete (foo, {}),
        mongo:insert_all (foo, [{x,1}, {x,2}, {x,3}, {x,0}, {x,-1}]),
        Cur = mongo:find (foo, {'$query', {}, '$orderby', {x,1}}, {'_id',0}, 0, 3),
        mongo:rest (Cur) end),
    mongo:disconnect (Conn),
    [{x,-1}, {x,0}, {x,1}] = Docs.

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