ActiveRecord（CDbCriteria）与QueryBuilder？ [英] ActiveRecord (CDbCriteria) vs QueryBuilder?

问题描述

我必须做一些筛选，例如找一个给定部门的人员，我想知道这样做的最佳方法。

I have to make some filters, such as get persons who are in a given department, and I was wondering about the best way to do it.

有些它们将需要连接多个表。

Some of them are going to require the join of multiple tables.

有人知道 CDbCriteria 和Query之间的主要区别吗？建造者？我特别想知道与数据库的兼容性。

Does anyone know about the main differences between CDbCriteria and Query Builder? I would particularly like to know about the compatibility with databases.

我在关于查询生成器的Yii文档中发现了这一点：

I found this in the Yii documentation about Query Builder:

它提供一定程度的数据库抽象，从而简化了向不同数据库平台的迁移。

It offers certain degree of DB abstraction, which simplifies migration to different DB platforms.

是CDbCriteria对象是否相同？更好吗？

Is it the same for the CDbCriteria objects? Is it better?

推荐答案

工作时会使用 CDbCriteria 的概念与Yii的活动记录（AR）抽象（通常是的时间）。 AR要求您创建模型

The concept of CDbCriteria is used when working with Yii's active record (AR) abstraction (which is usually all of the time). AR requires that you have created models for the various tables in your database.

查询生成器是一种非常不同的访问数据库的方式；实际上，它是一个结构化的包装程序，可让您以编程方式构造SQL查询，而不仅仅是将其写为字符串（此外，它还提供了一定程度的数据库抽象功能，如您所提到的那样）。

Query builder a very different way to access the database; in effect it is a structured wrapper that allows you to programmatically construct an SQL query instead of just writing it out as a string (as an added bonus it also offers a degree of database abstraction as you mention).

在典型的应用程序中，几乎不需要使用查询生成器，因为AR已经提供了很多功能，并且还提供了相同程度的数据库抽象。

在某些情况下，您可能想运行非常特殊的查询类型，该查询不方便或无法通过AR发出。然后，您有两个选择：

In some cases you might want to run a very specific type of query that is not convenient or performant to issue through AR. You then have two options:

1. 如果查询是固定的或几乎固定的，则可以通过 DAO ;实际上，查询生成器文档中提到如果查询很简单，则直接编写SQL语句会更容易，更快。


2. 如果需要动态构建查询，则查询生成器将变为

1. If the query is fixed or almost fixed then you can simply issue it through DAO; in fact the query builder documentation mentions that "if your queries are simple, it is easier and faster to directly write SQL statements".
2. If the query needs to be dynamically constructed then query builder becomes a good fit for the job.

因此，如您所见，查询生成器在大多数时候并不是很有用。仅当您要编写非常自定义且同时动态构造的查询时，才有意义使用它。

So as you can see, query builder is not all that useful most of the time. Only if you want to write very customized and at the same time dynamically constructed queries does it make sense to use it.

您提到的示例功能可以并且应该实现使用AR。

The example feature that you mention can and should be implemented using AR.

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