NPoco/PetaPoco Fetch()获取所有数据然后过滤客户端是否正常?

本文介绍了NPoco/PetaPoco Fetch()获取所有数据然后过滤客户端是否正常?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我已经注意到NPoco(或PetaPoco)的工作方式存在巨大差异，具体取决于您使用LINQ时调用的函数.

I've noticed a huge difference in how NPoco (or PetaPoco) works depending on which function you call when you are using LINQ.

例如，比较Fetch()和Query()两者似乎都做相同的事情:

For instance compare Fetch() which Query() which both appear to do the same thing:

A :Fetch<EntryImage>().Where(t => t.EntryType == type && t.EntryID == entryID);

B :Query<EntryImage>().Where(t => t.EntryType == type && t.EntryID == entryID);

A 返回表中的每一行(10,000+)，然后过滤客户端.

A returns every row in the table (10,000+) and then filters client side.

B 仅返回我期望的一个行.

B returns just the one row I'm expecting.

我发现这种行为非常危险-在没有真正注意的情况下编写性能很差的代码非常容易.这是预期的行为吗?如果这是正常行为，是否有任何方法可以获取以这种方式工作的方法列表，因此我可以避免在可能的情况下使用它们?

I find this behavior is quite dangerous - it would be very easy to write very badly performing code without really evening noticing. Is this expected behavior? If this is normal behavior, is there any way to get a list of methods which work this way, so I can avoid using them where possible?

推荐答案

这是NPoco的预期行为.

This is expected behavior for NPoco.

根据来源:

提取返回列表.

Fetch returns a list.

    /// <summary>
    /// Fetch all objects of type T from the database using the conventions or configuration on the type T. 
    /// Caution: This will retrieve ALL objects in the table
    /// </summary>
    List<T> Fetch<T>();

查询返回IQueryProviderWithIncludes(类似于IQueryable)

    /// <summary>
    /// Entry point for LINQ queries
    /// </summary>
    IQueryProviderWithIncludes<T> Query<T>();

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