Types

• Types are a way to create a common definition for columns and reuse it in multiple entities/scenarios
• For example the migrated Northwind application has the OrderID type that isused in the Orders class and the OrderDetails class
• Go the the "NorthwindBase" project, to the "Types" namespace (Folder)
• Add a new type called "StudentId" using the "Type" template
• Make sure that the base class represents the column type you want (NumberColumn in this case)
• Note that you can create a type based on a type
• Send the Base constructor the Name and the Format you want for the type.
• Set all the properties in the constructor

using System;
using System.Collections.Generic;
using System.Text;
using Firefly.Box;
using ENV.Data;

namespace Northwind.Types
{
    public class StudentId : NumberColumn
    {
        public StudentId() : base("Id", "5")
        {
            AllowNull = false;
        }
    }
} 

Use the type in the "Students" entity

using System;
using System.Collections.Generic;
using System.Text;
using Firefly.Box;
using ENV.Data;

namespace Northwind.Models
{
    public class Students : Entity
    {
        [PrimaryKey]
-       public readonly NumberColumn Id = new NumberColumn("Id", "5"){ AllowNull = false };
        public readonly Types.StudentId Id = new Types.StudentId();
        public readonly TextColumn LastName = new TextColumn("LastName", "30");
        public readonly TextColumn FirstName = new TextColumn("FirstName","30");
        public readonly Index SortById = new Index() { Unique = true };
        public readonly Index SortByName = new Index() { Unique = true };

        public Students()
            : base("Students", Northwind.Shared.DataSources.Northwind1)
        {
            SortById.Add(Id);

            SortByName.Add(LastName, FirstName, Id);
        }

    }
} 

• Exercise Types

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