首先，您可以通过使用唯一索引或约束来防止表中出现重复项。索引/约束可以按照以下建议协同工作。如果仅使用唯一索引而不是以下解决方案之一，则插入重复记录将引发错误，并且您将需要在另一端进行处理。

First, you can prevent a duplicate from ever occurring in the table by using a unique index or constraint. An index/constraint can work in concert with the suggestions below. If you only use a unique index and not one of the below solutions, inserting a duplicate record will throw an error and you will need to handle that on the other end.

另外，我可能会通过存储过程插入数据，以检查该行是否已存在。为此，您可以使用 MERGE 语句，如伪代码所示：

Additionally, I would probably insert the data via a stored procedure that checks to see if the row already exists. To do that, you can use either a MERGE statement, as shown in this pseudo code:

create procedure MyProcedure
(
    @Name nvarchar(100),
    ...
)
as

merge MyTable
using
(
    select @Name,...
) as source (Name, ...)
on MyTable.Name = source.Name
when not matched then
    insert (Name,...) values (source.Name,...)
when matched then
    update set Name = @Name,...

或者，您可以检查记录是否存在并手动插入或更新：

or, you could check for the records existence and insert or update manually:

create procedure MyProcedure
(
    @Name nvarchar(100),
    ...
)
as

    if not exists (select * from MyTable where Name = @Name)
    begin
        insert into MyTable (Name,...) values (@Name,...)
    end
    else
    begin
            update MyTable
            set ...
            where Name = @Name
    end