我需要创建一张新的费用卡答案

【问题标题】：I need to create a new expense card我需要创建一张新的费用卡
【发布时间】：2022-11-11 06:53:10
【问题描述】：

我需要创建一张新的消费卡，输入参数是金额、日期和描述。

创建费用卡必须填写的字段：持卡人是联系方式 Months Expenses Applications 是一个自定义对象

创建费用卡时，如果在“日期”字段中输入的日期之前存在 Months Expenses Applications，则会创建一个新的费用卡，从现有的 Months Expenses Applications 中获取

如果在“日期”字段中输入的日期之前没有月份费用应用程序，您需要创建月份费用应用程序，然后创建一个费用地图，其中月份费用应用程序将创建一个新的月份费用应用程序

我试图创建一个“金额”“日期”“描述”等于输入参数的费用地图，但我不知道如何指定 MonthExpenseApplication__c

public static void createNewExpenseCard(Integer amount, Date createdDate, String description) {
        
        Month_Expense_Application__c MonthApplication = [
            SELECT Name, MonthDate__c
            FROM Month_Expense_Application__c
            WHERE MonthDate__c =: createdDate
        ];
        if (MonthApplication != null) {
            ExpenseCard__c exp = new ExpenseCard__c(
                Amount__c = amount,
                CardDate__c = createdDate,
                Description__c = description,
                CardKeeper__c = '0034x00001K7kGCAAZ'
            );
            exp.MonthExpenseApplication__c = [
                SELECT MonthExpenseApplication__c
                FROM ExpenseCard__c 
                WHERE MonthExpenseApplication__c =: MonthApplication.Id
            ].Id;
            insert exp;
        } else {
            Month_Expense_Application__c monthApp = new Month_Expense_Application__c(
                Balance__c = 1000,
                MonthDate__c = createdDate,
                Keeper__c = '0034x00001K7kGCAAZ'
            );
            ExpenseCard__c exp2 = new ExpenseCard__c(
                Amount__c = amount,
                CardDate__c = createdDate,
                Description__c = description,
                CardKeeper__c = '0034x00001K7kGCAAZ'
            );
            
            insert exp2;
        }
        
    }

【问题讨论】：

标签： salesforce apex lwc

【解决方案1】：

这是危险的：

Month_Expense_Application__c MonthApplication = [
            SELECT Name, MonthDate__c
            FROM Month_Expense_Application__c
            WHERE MonthDate__c =: createdDate
        ];

如果结果为零，它将抛出“list has no rows for assignment”。如果超过 1 则类似。

像这样的东西？

Integer amount = 50;
Date createdDate = System.today();
String description = 'Lorem ipsum...';

Month_Expense_Application__c app;

List<Month_Expense_Application__c> applications = [SELECT Id
    FROM Month_Expense_Application__c
    WHERE MonthDate__c =: createdDate
    LIMIT 1];

if(applications.isEmpty()){
   app = new Month_Expense_Application__c(
      Balance__c = 1000,
      MonthDate__c = createdDate,
      Keeper__c = '0034x00001K7kGCAAZ'
   );
   insert app;
} else {
   app = applications[0];
}

// one way or another - the monthly allowance exists now. So just use its id in the lookup

ExpenseCard__c exp = new ExpenseCard__c(
   Amount__c = amount,
   CardDate__c = createdDate,
   Description__c = description,
   CardKeeper__c = '0034x00001K7kGCAAZ',
   Month_Expense_Application__c = app.Id
);

有更优雅的方法可以做到这一点，您需要阅读有关 upsert 和外部 id 的信息 - 但它应该足够好。

【讨论】：