mongodb-一个集合中的许多文档与许多集合中的文档 [英] mongodb - many documents in one collection vs many collection
问题描述
我正在使用mongodb作为数据库存储.
I'm using mongodb as database storage.
我的网络应用必须收集用户回复.
my web app has to collect user responses.
用户响应是mongodb中的文档(或sql中的一行).文件长度大约为10〜200.
a user response is a document in mongodb (or a row in sql). length of a document is about 10~200.
用户响应已分类(仅一类).对于每个类别，用户响应的数量在100到5000之间.如果两个文件属于同一类别，则长度相同. (或者它们在sql中具有相同的列)
user responses are categorized(to only one category). for each category, number of user response is between 100~5000. if two document is in same category, the have same length. (or they have same columns in sql)
可以根据管理员的请求动态创建/删除类别.
a category can be dynamically created/deleted by request of admins.
目前，我的数据结构是
category collection
{_id, 'name' : 'c1', 'somevalue' : '123'}
{_id, 'name' : 'c2', 'somevalue' : '23'}
{_id, 'name' : 'c3', 'somevalue' : '143'}
{_id, 'name' : 'c4', 'somevalue' : '153'}
...
'c1' collection
{ userresponse1 }
{ userresponse2 }
{ userresponse3 }
...
'c2' collection
{ userresponse1 }
{ userresponse2 }
{ userresponse3 }
...
'c3' collection
{ userresponse1 }
{ userresponse2 }
{ userresponse3 }
...
'cN' collection
{ userresponse1 }
{ userresponse2 }
{ userresponse3 }
..
这是一个明智的决定吗?我担心通过为每个类别分配一个集合来使事情变坏的可能性.如果我有很多馆藏，会有一些性能问题吗?我应该合并我的收藏集并为用户响应提供一些标识符吗?
Is this a wise decision? I'm worried about possibility of something going bad by assigning a collection for each category. will there be some performance issues if I have many collections? should I merge my collections and give the userresponses some identifiers instead?
推荐答案
当然，答案取决于您的查询模式以及要查找的集合数.在不了解更多信息的情况下，我怀疑您将需要进行跨越许多响应集合的查询.
Of course the answer depends on you query patterns and how many collections you're looking at having. Without knowing more, I would suspect that you would need to make queries that span many of the response collections.
例如，如果每个userresponse都有一个userId字段，并且假设您想获取特定用户所有响应的日期排序列表.您将需要遍历所有集合，对每个集合进行查询，然后将结果合并到客户端代码中.显然，与带索引的UserResponse集合中的单个简单查询/排序相比，这将是非常低效的.
For example if each userresponse had a userId field and suppose you wanted to get a date sorted list of all the responses for a specific user. You would need to loop over all the collections, query each, and combine the results in client code. Obviously this would be highly inefficient compared to a single simple query/sort in an indexed UserResponse collection.
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