Problem find record in DataTable

Question

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I have 2 tables:
Order(id,date,idWordker,idCustomer) Primakey key:id
OrderDetail(id,idProduct,quantity,price) Primakey key:id
You can see 2 keys in OrderDetail.I need to update the quantity
I use:

C#

public DataTable AddCart(string id, string idProduct,int quantity,int price)
{
        DataTable tbCart = new DataTable();
        tbCart = (DataTable)HttpContext.Current.Session["Cart"];
        if (tbCart == null)
            tbCart = MakeCart();
        DataRow dr = tbCart.NewRow();
        dv = tbCart.DefaultView;
        dv.Sort = "idProduct";
        rIndex = dv.Find(idProduct);
        if (rIndex != -1)
        {
            //update quantity
        }
        else
        {
                dr[0] = id;
                dr[1] = idProduct;
                dr[2] = 1;//quantity
                dr[3] = price;
        }
}

If OrderDetail exist idProduct,the quantity of product will be updated.Session["Cart"] will be insert into OrderDetail
How to find with 2 keys?

Posted 4-Jun-12 23:06pm

giatuan2011

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2 solutions

Solution 1

2 keys?

Which one of them is a unique reference point for a product? Pick and use the one that is unique based on your DB design and use. If both are unique, remove one key as it's not needed.

Posted 4-Jun-12 23:12pm

Sandeep Mewara

Comments

giatuan2011 5-Jun-12 5:17am

They are primakey key.
I think the OrderDetail has more products

Sandeep Mewara 5-Jun-12 5:44am

2 primary key?

giatuan2011 5-Jun-12 5:36am

I just added:
tbCart.Rows[rIndex][2]=int.Parse(tbCart.Rows[rIndex][2].ToString())+slxuat;
But I have new problem.I need to create the "id" after assigning tbCart to Session ["Cart"].This only happens 1 time.I tried Random.It give me more id.How to make auto id?

Sandeep Mewara 5-Jun-12 5:45am

Set the column in DB as IDENTITY column and set auto increment to 1. This will automatically create ID in incremental manner whenever you insert a record in your database.

Espen Harlinn 5-Jun-12 9:23am

Good points :-D

Sandeep Mewara 5-Jun-12 9:31am

Thanks.

Maciej Los 5-Jun-12 14:50pm

Good answer, my 5!

Sandeep Mewara 6-Jun-12 0:37am

Thanks.

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VJ Reddy · Accepted Answer · 2012-06-04T23:21:00

Solution 2

As stated in the question only Id is the primary key in OrderDetail and idProduct is another id.
Hence, I think the Select method of DataTable can be used to find the required row as follows:

C#

DataRow[] rows = tbCart.Select(
        string.Format("id='{0}' and idProduct='{1}'",id,idProduct),
        idProduct, DataViewRowState.CurrentRows);
if (rows.Length > 0){
   rows[0]["quantity"]= 
   rows[0]["price"]=
}

Posted 4-Jun-12 23:21pm

VJ Reddy

Comments

giatuan2011 5-Jun-12 5:38am

Your solution is work.
But I have new problem.I need to create the id after assigning tbCart to Session ["Cart"].This only happens 1 time.I tried Random.It give me more id.How to make auto id?

VJ Reddy 5-Jun-12 5:42am

The Guid.NewGuid().ToString() can be used to generate a unique ID.

Espen Harlinn 5-Jun-12 9:23am

Neat :-D

VJ Reddy 5-Jun-12 9:40am

Thank you, Espen :)

Maciej Los 5-Jun-12 14:50pm

Good answer, my 5!

VJ Reddy 5-Jun-12 19:39pm

Thank you, losmac :)