Sharepoint 2010 : Data Access Overview - Columns (part 1)

static void Main(string[] args)
 {
   string siteUrl = "http://localhost";
   List<string> fieldNames = new List<string>();
   Program p = new Program();

   using (SPSite site = new SPSite(siteUrl))
   {
     using (SPWeb web = site.OpenWeb())
     {
       SPContentType newContentType;
       newContentType = p.CreateContentType(web,
                             "MyFirstContentType",
                             "Item");

       p.CreateSiteColumn(web, "MyColumn",
                               SPFieldType.Text,
                               false);

       fieldNames.Add("MyColumn");

       p.CreateSiteColumn(web, "MyColumn2",
                               SPFieldType.Text,
                               false);

       fieldNames.Add("MyColumn2");
       p.AddFields(web, fieldNames.ToArray(), newContentType);

       Console.WriteLine("{0} | {1} | {2}", "Title".PadRight(20),
                                            "Type".PadRight(20),
                                            "Group".PadRight(20));
       Console.WriteLine(new string(′-′, 70));

       foreach (SPField fld in newContentType.Fields)
       {
         Console.WriteLine("{0} | {1} | {2}", fld.StaticName.PadRight(20),
                                                  fld.TypeDisplayName.PadRight(20),
                                                  fld.Group.PadRight(20));
       }
     }
   }
   Console.ReadLine();
 }


 void CreateSiteColumn(SPWeb web, string name, SPFieldType fieldType,
                                                     bool isRequired)
 {
   if (!web.AvailableFields.ContainsField(name))
   {
     web.Fields.Add(name, fieldType, isRequired);
   }
 }

 void AddFields(SPWeb web, string[] fieldNames, SPContentType contentType)
 {
   foreach (string fieldname in fieldNames)
   {
     if (web.Fields.ContainsField(fieldname))
     {
       SPFieldLink fieldLink = new SPFieldLink(web.Fields[fieldname]);
       contentType.FieldLinks.Add(fieldLink);
     }
   }
   //Update should be called to persist these changes
   //contentType.Update();
 }