地图中的顶点地图

Question

我需要在我的触发器之一的Map中有一个Map。我知道如何初步构建地图，如文档所示：

Map<Id, Map<Id, Addendum__c>> addendums = new Map<Id, Map<Id, Addendum__c>>{};

但是，我在实际为多维映射赋值时遇到了问题。通常，我会使用.put()将值放入一维映射中。也许我仍然应该使用这个函数，但我永远也找不到正确的语法。

我已经尝试了以下不起作用的方法：

addendums.put(addendum.Opportunity__c, addendum.Id, addendum);

addendums.put(addendum.Opportunity__c, (addendum.Id, addendum));

有人知道怎么做吗？

谢谢!

Answer 1

使用您的示例代码将会起作用，当然二级映射只能有一个条目，如果您处于可能需要更多条目的情况下，则下面的代码将为您完成此任务：

// This line creates the map in the proper format
Map<Id,Map<Id,Addendum__c>> addendums = new Map<Id,Map<Id,Addendum__c>>{};

// This for loop goes through each addendum and first places it into a single dimension map.  
// Once that map is created, it is placed into the final multi-dimensional
for(Addendum__c addendum : [SELECT Id,Opportunity__c FROM Addendum__c WHERE Opportunity__c IN :oppBatch])
{
    if(addendums.get(addendum.Opportunity__c) == null)
    {
        addendums.put(addendum.Opportunity__c, new Map<Id, Addendum__c>{addendum.Id => addendum);
    }
    else
    {
        addendums.get(addendum.Opportunity__c).put(addendum.Id, addendum);
    }
}

正如您所看到的，在第一个映射上使用get()来获得正确的第二级映射，我们希望在其中添加一个附录。

Answer 2

Josh提供的方法运行良好。如果你想删除一行代码，你可以使用以下方法：

Map<Id, Map<Id,Addendum__c>> addendums = new Map<Id,Map<Id,Addendum__c>>();
for(Addendum__c addendum : [SELECT Id,Opportunity__c FROM Addendum__c WHERE Opportunity__c IN :oppBatch]){
    addendums.put(addendum.opportunity__c, new Map<Id, Addendum__c>{addendum.id => addendum});
}

我不知道还有比这更有效的方法。

Answer 3

我找到了一种方法来做到这一点，尽管我不确定这是否是最有效的方法。所以如果你有更好的解决方案，请让我知道，我会将“解决方案”积分转移给你。

我所做的是分配第一个地图，然后将该地图放在最终地图中。

// This line creates the map in the proper format
Map<Id,Map<Id,Addendum__c>> addendums = new Map<Id,Map<Id,Addendum__c>>{};

// This for loop goes through each addendum and first places it into a single dimension map.  
// Once that map is created, it is placed into the final multi-dimensional
for(Addendum__c addendum : [SELECT Id,Opportunity__c FROM Addendum__c WHERE Opportunity__c IN :oppBatch]){
    Map<Id,Addendum__c> thisAddendum = new Map<Id,Addendum__c>{ addendum.Id => addendum };
    addendums.put(addendum.Opportunity__c,thisAddendum);
}