如何删除数组索引中除第 0 条记录外的所有记录

Question

根据代码，我不想删除第 0 条记录并删除其余记录。但是它正在删除所有记录！

如有错误请指正。

代码如下：

list<account> scope = [Select Id,(Select id,CreatedDate,ebMobile__FileType__c,ebMobile__Account__c from Files__r order by CreatedDate DESC) from account where id in ('0016D00000444','0016D000000ugO')]; 
        Set<Id>OldIds = new Set<Id>();
        Set<Id>newIds = new Set<Id>();
        Set<Id> rIds = new Set<Id>();
        Set<Id> rrIds = new Set<Id>();
        list<File__c> listmemb = new list<File__c>();
        List<File__c> listmemb3 = new List<File__c>();
        List<File__c> listmemb4 = new List<File__c>();
        for(Account Acc : scope)
        {
            for(File__c fi : Acc.ebMobile__Files__r)
            {
                listmemb = [select id,CreatedDate,ebMobile__FileType__c from File__c where id =: fi.id];
                if(fi.ebMobile__Account__c != Null)
                {
                    for(Integer i=0; i<listmemb.size(); i++)
                    {
                        if(fi.ebMobile__FileType__c == 'Signature' && i==0)
                        {
                            rIds.add(listmemb[0].id); // Exclude 0th record 
                        }
                        if(i>0 && listmemb[i].ebMobile__FileType__c == 'Signature' || i > 0 && listmemb[i].ebMobile__FileType__c != 'signature')
                        {
                            rrIds.add(listmemb[i].id); // Delete all record excluding 0th record
                        }
                        if(fi.ebMobile__FileType__c != 'Signature')
                        {
                            OldIds.add(fi.id);  
                        }
                    }
                }
            }
        }
        listmemb3 = [Select id,CreatedDate,ebMobile__FileType__c from File__c where id in : OldIds];
        listmemb4 = [Select id,CreatedDate,ebMobile__FileType__c from ebMobile__File__c where id in : rrIds];
        if(listmemb3.size() > 0 && listmemb4.size()>0)
        {
            delete listmemb3;
            delete listmemb4;
        }
    }

Answer 1

代码中有很多不必要的检查和列表

让我们简化一下：

list scope = [Select Id,(Select id,CreatedDate,ebMobile__FileType__c,ebMobile__Account__c from Files__r order by CreatedDate DESC) from account where id in ('XXXXXXXXXXXXXXXX','XXXXXXXXXXXXXXXX')];//Always keep Ids encrypted while posting on public platform
SetOldIds = new Set();
SetnewIds = new Set();
Set rIds = new Set();
Set rrIds = new Set();
list listmemb = new list();
List listmemb3 = new List();
List listmemb4 = new List();
for(Account Acc : scope)
{
    Integer i= 0; //This will be used to exclue the first element
    for(File__c fi : Acc.ebMobile__Files__r)
    {
        //listmemb = [select id,CreatedDate,ebMobile__FileType__c from File__c where id =: fi.id];//You don't need this as you already have fi
        //if(fi.ebMobile__Account__c != Null)We are getting fi from Acc so it won't be having ebMobile__Account__c as null, assuming it as lookup
        //{
            //for(Integer i=0; i {This is syntactically wrong
                /* This whole section is not needed as rIds is not being used anywhere
                if(fi.ebMobile__FileType__c == 'Signature' && i==0)
                {
                    rIds.add(listmemb[0].id); // Exclude 0th record
                }
                */
                //if(i>0 && listmemb[i].ebMobile__FileType__c == 'Signature' || i > 0 && listmemb[i].ebMobile__FileType__c != 'signature')
                if( i > 0 ) //Just put the check you need
                {
                    rrIds.add(listmemb[i].id); // Delete all record excluding 0th record
                }
                if(fi.ebMobile__FileType__c != 'Signature')
                {
                    OldIds.add(fi.id);
                }
                i++;
            //}
        //}
    }
}
listmemb3 = [Select id,CreatedDate,ebMobile__FileType__c from File__c where id in : OldIds];
listmemb4 = [Select id,CreatedDate,ebMobile__FileType__c from ebMobile__File__c where id in : rrIds];
if(listmemb3.size() > 0 && listmemb4.size()>0)
{
    delete listmemb3;
    delete listmemb4;
}
}

希望对您有所帮助。

Answer 2

@Vishal 根据您的代码和上下文，有几件事我不太确定：

什么定义了 'the first file'？在您的第二个（重复）查询中，您似乎没有应用任何排序，因此 Salesforce 可能 return 您会根据数据库结构以不同的顺序排列相同的记录。在您的第一个子 select 查询中有。
您使用 if、if、if 而不是 if、else if、else if 是否有特定原因？使用这种方法，您可以防止第二项和第三项成为运行，即使第一项已应用。这将简化您的代码，因为您不需要所有重复检查（i == 0、i > 0 等）
不同的 Salesforce 记录（文件与 ebMobile__File__c）怎么可能有相同的 Salesforce ID？（在您对 listMembers 的查询中）

一对建议：

使用Offset(shift起始记录)只查询真正要删除的记录
请尽量避免在循环中执行查询和 DML 操作，因为这对性能不利，而且还可能导致运行进入调控器限制
应用 variableBinding 的用法，这将确保不会应用 SOQL 注入（例如，当帐户 ID 从前端获取时）
简化你的逻辑，做你真正想做的事；如果您只查询要删除的文件（请参阅 1.），那么您可以简单地循环查询以确定签名条件，然后只删除每个帐户的文件列表。在我看来，不需要再次查询文件，因为你已经有了他们的ID和记录，所以你可以简单地指定删除检索到的记录，对吗？

Set<Id> accountIds = new Set<Id>{ 'xxxx', 'xxxx' };
List<Account> scope = [SELECT Id,
                            ( SELECT Id, ... 
                              FROM Files__r 
                              ORDER BY CreatedDate DESC
                              OFFSET 1 )
                         FROM Account 
                        WHERE Id IN :accountIds];
List<File> filesToDelete = new List<File>();
List<ebMobile__File__c> ebMobileFileToDelete = new List<File>();
for( Integer i = 0, j = scope.size(); i < j; i++ ){
   Account acc = scope[ i ];
   if( acc.Files__r != null & !acc.Files__r.isEmpty() ){
      for( Integer k = 0, l = acc.Files__r.size(); k < l; k++ ){
         File f = acc.Files__r[ k ];
         if( f.ebMobile__FileType__c != 'Signature' ){
            // When not signature, delete the original file
            filesToDelete.add( f );
         } else{
             // Don't delete the File, but delete the EB MobileFile
             ebMobileFileToDelete.add( new ebMobile__File__c( Id = f.Id ) );
         }
      }
   }
}
if( !filesToDelete.isEmpty() ){ delete filesToDelete; }
if( !ebMobileFileToDelete.isEmpty() ){ delete ebMobileFileToDelete; }

请注意，我没有运行这段代码，因此可能需要进行一些调整，但我希望你能够使它全部正常工作。

祝你好运，享受！雷尼尔

如何删除数组索引中除第 0 条记录外的所有记录

how to delete all records excluding 0th record in array index

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