Question

I am using c#, sqlce, datatable. I select products with this query:

select price from products where productid=myproduct and mydate between startdate and finaldate and clientid=myclient

But it’s going to take much time.
So I could use a datatable to store products:

datatable prices = new datatable(); 
prices=this.returntable("select productid,startdate,finaldate,client from products")


 for(int i=0;i<allproductsihave;i++) {
    product.newprice=this.getmyprice(prices,product.client,product.id,product.date);
 }


 private decimal getmyprice(datatable products,string myclient, string myproduct, datetime mydate)
 {
   //how do I do at here the equivalent to first sql query?
   //for select a product from a datatable where my date is between 2 dates,
   //and client=myclient and productid=myproduct
   return Convert.Todecimal(datatable.prices[something]["price"].tostring());
 }

In this way I shouldn’t connect to the database for each product query.
Is it posible?

maybe doing convert.todatetime to startdate and finaldate?

Answer 1

The DataTable.Select() method accepts a string representing a “where” condition and returns an array of DataRow containing matching rows.

Datarow[] products = prices.Select(string.Format("'{0}'>='{1}' AND '{0}'<='{2}'", mydate, startdate, finaldate));

Mind the date format!! It must be sql compliant.