好人们帮我翻译下这些代码...我要做毕业设计啊

/*这是一个往表ShopCart中插数据的存储过程*/
CREATE Procedure [dbo].[AddItemtoShoppingCart]
(
    @CartIDString nvarchar(50),
    @BookID int,
    @BookQuantity int                            /*声明三个输入参数（与表中的三列是对应的）*/
)
As

DECLARE @CountItems int

SELECT
    @CountItems = Count(BookID)
FROM
    ShopCart
WHERE
    BookID = @BookID
  AND
    CartIDString = @CartIDString                /*判断表中是否已经有要插入的书*/

IF @CountItems > 0  

    UPDATE
        ShopCart
    SET
        BookQuantity = (@BookQuantity + ShopCart.BookQuantity)
    WHERE
        BookID = @BookID
      AND
        CartIDString = @CartIDString                          /*如果有，就把图书数量改为原有的加上要插入的*/

ELSE  

    INSERT INTO ShopCart                                   
    (
        CartIDString,
        BookQuantity,
        BookID
    )
    VALUES
    (
        @CartIDString,   
        @BookQuantity,
        @BookID                                              /*如果没有，就把该书插入表中*/
    )
GO