Question: I am working on a service which tracks millions of products for price changes and needs to be able to let the users view price history, biggest discounts , prices change a few times per week sometimes per day.

right now I have 

products table

* id
* category\_id
* name
* photo
* sku
* supplier\_id
* link
* discount (difference from last price to current price)

prices table

* product id
* timestamp
* price

I need to be able to query for:
biggest discounts
biggest discounts per category
biggest discounts per supplier
history of price for one product

is mongoDB a good fit ? can anyone give a quick start on how to convert my tables to fit the app ?

Answer: 
You can place a Main method in every class you declare. Some programmers take advantage of this to build a small test app into each class they declare. 

However, if you declare more than one **Main method** among the classes of your project, you’ll need to indicate to the IDE which one you would like to be the app’s **entry point**. To do so:

1. With the project open in Visual Studio, select **Project >
[ProjectName] Properties**... (where **[ProjectName]** is the name of your
project).
2. Select the class containing the Main method that should be the entry
point from the **Startup object** list box.
You can put more then one main method in single program but program with one main method will be compiled at a time for example :
Copy paste this code in editor and change name Release in first line and see the change 

```
#define Release 
using System;
class Program
{  
#if Release==true
    public static void Main(string[] args) //for enemy
    {     
        Console.WriteLine("go to  hell");
        Console.ReadLine();
    }

#elif Release==false
    static void Main(string[] args) //for friend
    {    

         Console.WriteLine("hello ");

        Console.ReadLine();
    }

#endif 
}

```