ADO Net C# Tutorial

using System;
using System.Data;
    class Program
    {
        static void Main(string[] args)
        {
            DataTable dt = new DataTable("Table-1");
            dt.Columns.Add("Id", typeof(int));
            dt.Columns.Add("Field1", typeof(string)).MaxLength = 50;
            UniqueConstraint uc1 = new UniqueConstraint("UniqueConstraint", dt.Columns["Field1"]);
            dt.Constraints.Add(uc1);
            OutputConstraintProperties(dt);
        }
        private static void OutputConstraintProperties(DataTable dt)
        {
            Console.WriteLine(dt.TableName);
            Console.WriteLine(dt.Constraints[0].ConstraintName);
            Console.WriteLine(((UniqueConstraint)dt.Constraints[0]).IsPrimaryKey);
            foreach (DataColumn col in ((UniqueConstraint)dt.Constraints[0]).Columns)
            {
                Console.WriteLine(col.ColumnName);
            }
        }
    }