Question

我有一张桌子说，交易有两个外键。一个外键引用客户表，另一个外键引用BillAmount表。所以我的POCO就像

public class Transaction
{
    public string Id { get; set; }
    public string CustomerId { get; set; }
    public string BillAmountId { get; set; }
}

public class Customer
{
    public string Id {get;set;}
    public string Name {get;set;}
}

public class BillAmount
{
    public string Id {get;set;}
    public double Amount {get;set;}
}

当我尝试插入新的Transaction对象时，我注意到总共对数据库进行了3次调用：

要获取与Customer对象中存在的ID对应的Transaction记录
要获取与BillAmount对象中存在的ID对应的Transaction记录
INSERT命令最终插入一个新的Transaction对象

如何防止电话1）和2）？

Answer 1

首先，如果您使用ORM工具（如EF核心），则应根据它来重新组织实体；

public class Transaction {
    public string Id { get; set; }
    public Customer Customer { get; set; }
    public BillAmount BillAmount { get; set; }
}

public class Customer {
    public string Id { get; set; }
    public string Name { get; set; }
}

public class BillAmount {
    public string Id { get; set; }
    public double Amount { get; set; }
}

当您按如下所示致电时，它会在一笔交易（一次插入）中完成您的工作。

public void InsertTransaction() {
        //Some dummy data
        Customer customer = new Customer();
        customer.Id = "5";
        customer.Name = "George";

        BillAmount billAmount = new BillAmount();
        billAmount.Id = "7";
        billAmount.Amount = 2.0;

        Transaction transaction = new Transaction();
        transaction.Id = "1";
        transaction.Customer = customer;
        transaction.BillAmount = billAmount;

        //Complete in one insert
        context.Transaction.Add(transaction);
        context.SaveChanges();
    }

如何避免在EF Core中插入具有相关实体的对象的多个数据库调用

1 个答案: