UserDefinedTable userDefinedTable = UserDefinedTableSubSystem.Instance.Load(typeof(Store));
UserDefinedField userDefinedField = userDefinedTable.CreateField();
userDefinedField.FieldName = "U_ABC";
userDefinedField.Description = ""U_ABC_Description";
userDefinedField.DataType = UserDefinedFieldDataType.String;
userDefinedField.DataLength = 100;
userDefinedField.IsSearchable = false;
userDefinedField.IsMandatory = false;
userDefinedField.DisplayOnly = false;
userDefinedField.ShowInResults = false;
userDefinedField.RegularExpression = "";
userDefinedTable.AddField(userDefinedField);
CXS.Retail.BusinessLogic.UDFHelperClass.CommitUserDefinedFields(userDefinedTable);