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[英]How to check if a record exists in the SQL Server database C# winform?
[英]How to check if record is exists in c#
我将数据插入如下所示的数据库中:
var N_ID = " 001T ";
var N_Email = N_EmailAdd;
TourCenterDBEntities NewsLetterEntities = new TourCenterDBEntities();
News_Letter NewsLetterDetails = new News_Letter();
NewsLetterDetails.N_id = N_ID;
NewsLetterDetails.N_Email = N_Email;
NewsLetterEntities.News_Letter.Add(NewsLetterDetails);
NewsLetterEntities.SaveChanges();
记录可以正确保存到数据库中,但是在我插入之前我想知道该记录是否存在。我该怎么做。
在插入之前,您可以像这样检查:
if(NewsLetterEntities.Any(entity => entity.N_id == N_ID)) {
// Return or throw, your choice
}
我找到了一种方法来解决这个问题。
var existing = NewsLetterEntities.News_Letter.Where(l => l.N_Email == N_EmailAdd);
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