前言
插入数据之前,有时候需要检测该数据是否已经存在数据库里。
解决方案
可采用以下语句判断
db.Orderss.Any(o => o.Transaction == txnId)
示例代码:
using (WebApplication1Entities db = new WebApplication1Entities())
{
if (db.Orderss.Any(o => o.Transaction == txnId)) return;
Orders order = new Orders();
order.UserId = userId;
order.Date = System.DateTime.Now;
order.Transaction = txnId;
order.Amount = Convert.ToDecimal(mcGross);
order.Email = payerEmail;
order.Country = residenceCountry;
db.Orderss.Add(order);
db.SaveChanges();
}