在列表中找到所有具有值的对象 [英] Find all objects with value in list

问题描述

我正在向Grails环境介绍自己（这是真棒）。我一直在收获动态生成方法的好处，如 findAllBy * 范围。但是，我遇到了一个问题，我不确定如何继续。在Google上花费的一小时对我来说并没有那么多。

问题

$ b $我有一个类如下：

  class Runner {
 
 static hasMany = [Owner：Owner] 
} 
  

在我的Owner控制器中，我希望找到所有 Runner 包含给定所有者的对象。实际上，我试图从多个到一个。

示例

如果我有一个所有者看起来像

 所有者[name =Dave] 
  

我有一个 Runner 类似于：

 Runner [拥有者[Owner [name =Dave]，Owner [name =James]]] 
  

我的查询应该返回这个 Runner 对象，但它不应该返回

  Runner [拥有者[Owner [name =Bill]，Owner [name =James]]] 
  

我的尝试

我试图使用 inList 扩展，但经过一些进一步的研究后，我意识到这是为其他方式设计的。我的代码目前如下：

  def runners（）{
 log.info（Runners） 
 List< Runner>亚军; 
业主; 
 
 if（params.id）{
 log.info（Id =+ params.id）; 
 owner = Owner.get（params.id）; 
 log.info（owner =+ owner.name）; 
 //在列表中抓住跑步者。 
 log.info（Number of results =+ runners.size（））; 
} 
 
 
 [results：results，jockeyInstance：jockey] 
} 
  

$经过对 HQL 的一些研究，我发现了一个更优雅的解决方案，它并不需要我完全可以改变 Domain 类。我使用的查询如下所示：

  runners = Runner.executeQuery（FROM Runner as r WHERE：owner in elements（r .owners），[owner：ownerInstance]）; 
  

其中 ownerInstance 是所有者用于映射到 Runner 的对象。

I'm introducing myself to the Grails environment (It's awesome). I've been reaping the benefits of dynamically generated methods like the findAllBy* range. However, I've come to a problem and I'm unsure about how to proceed. An hour spent on Google didn't yield all that much for me either.

Problem

I have a class like the following:

class Runner {

    static hasMany = [owners: Owner]
}

And in my Owner controller, I wish to find all Runner objects, that contain a given Owner. Effectively, I'm trying to go from the many to the one.

Example

If I have an Owner object, that looks something like

Owner[name="Dave"]

And I have a Runner with something like:

Runner[owners[Owner[name="Dave"], Owner[name="James"]]]

My query should return this Runner object, but it should not return

Runner[owners[Owner[name="Bill"], Owner[name="James"]]]

My attempts

I've attempted to use the inList extension, but after some further research I realised that was designed for the other way around. My code at the moment is as follows:

def runners() {
    log.info("Runners")
    List<Runner> runners;
    Owner owner;

    if (params.id) {
        log.info("Id = " + params.id);
        owner = Owner.get(params.id);
        log.info("owner = " + owner.name);
        // Grab runners in list thing.
        log.info("Number of results = " + runners.size());
    }


    [results: results, jockeyInstance: jockey]
}

解决方案

After some research into HQL, I found a more elegant solution that didn't require me to change the Domain classes at all. The query I used was as follows:

runners = Runner.executeQuery("FROM Runner as r WHERE :owner in elements(r.owners)", [owner : ownerInstance]);

Where ownerInstance is the Owner object being used to map to the Runner.

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