简单：首先检查它们是否已存在于数据库中，并且如果是，请不要插入它们......



如果没有您的数据和表格定义，我们就不能再说了。

0）使用约束 [ ^ ]（PrimaryKey，Unique）



1）在插入记录之前，检查该表中存在的值，如下所示的示例查询，如果count大于0则则存在值&你应该通知用户重复的值（或者根据你的要求生成不同的ID ....

  SELECT  COUNT（*） FROM  Table_Name  WHERE  Column_Name = '  SomeValue' 

how to we prevent duplicate value on database table through c# code when inserting details

Simple: check first to see if they are already in the database, and if they are, don't insert them...

Without your data and table definitions, we can say no more.

0)Use Constraints[^](PrimaryKey, Unique)

1)Before insert the record, check existence of the value in that table, sample query like below, if count is above 0 then value exists & you should notify the user about duplicate value(OR generate different ID....it's based on your requirement)

SELECT COUNT(*) FROM Table_Name WHERE Column_Name='SomeValue'