微软ASP.NET站点部署指南（9）：部署数据库更新
1. 综述
不管什么时候，程序都有可能像代码更新一样更新数据库。本章节你将进行数据库修改，测试，然后部署到测试环境和生产环境。
提醒：如果根据本章节所做的操作出现错误信息或一些功能不正常的话，请务必check Troubleshooting页面。
2. 给表添加新列
本小节，将修改Student和Instructor实体共同的基类Person类，添加一个birth date字段，也要在展示页面的表格上添加一个新列。
在ContosoUniversity.DAL项目，打开Person.cs在类的末尾添加如下的代码属性（记得，大括号里面哦）。
[DisplayFormat(DataFormatString = "{0:d}", ApplyFormatInEditMode = true)]
[Required(ErrorMessage = "Birth date is required.")]
[Display(Name = "Birth Date")]
public DateTime? BirthDate { get; set; }
需要更新初始化类来支持新列，打开SchoolInitializer.cs文件找到var students = new List<Student>开头的代码，替换成包括birth date信息的如下的爱吗：
var students = new List<Student>
{
new Student { FirstMidName = "Carson", LastName = "Alexander", EnrollmentDate = DateTime.Parse("2005-09-01"), BirthDate = DateTime.Parse("1990-01-01") },
new Student { FirstMidName = "Meredith", LastName = "Alonso", EnrollmentDate = DateTime.Parse("2002-09-01"), BirthDate = DateTime.Parse("1989-01-15") },
new Student { FirstMidName = "Arturo", LastName = "Anand", EnrollmentDate = DateTime.Parse("2003-09-01"), BirthDate = DateTime.Parse("1988-02-01") },
new Student { FirstMidName = "Gytis", LastName = "Barzdukas", EnrollmentDate = DateTime.Parse("2002-09-01"), BirthDate = DateTime.Parse("1987-03-15") },
new Student { FirstMidName = "Yan", LastName = "Li", EnrollmentDate = DateTime.Parse("2002-09-01"), BirthDate = DateTime.Parse("1985-11-11") },
new Student { FirstMidName = "Peggy", LastName = "Justice", EnrollmentDate = DateTime.Parse("2001-09-01"), BirthDate = DateTime.Parse("1970-11-21") },
new Student { FirstMidName = "Laura", LastName = "Norman", EnrollmentDate = DateTime.Parse("2003-09-01"), BirthDate = DateTime.Parse("1992-10-11") },
new Student { FirstMidName = "Nino", LastName = "Olivetto", EnrollmentDate = DateTime.Parse("2005-09-01"), BirthDate = DateTime.Parse("1986-06-06") }
};
将var instructors = new List<Instructor>开头的代码块替换成如下代码：
var instructors = new List<Instructor>
{
new Instructor { FirstMidName = "Kim", LastName = "Abercrombie", HireDate = DateTime.Parse("1995-03-11"), BirthDate = DateTime.Parse("1918-08-12") },
new Instructor { FirstMidName = "Fadi", LastName = "Fakhouri", HireDate = DateTime.Parse("2002-07-06"), BirthDate = DateTime.Parse("1960-03-15") },
new Instructor { FirstMidName = "Roger", LastName = "Harui", HireDate = DateTime.Parse("1998-07-01"), BirthDate = DateTime.Parse("1970-01-11") },
new Instructor { FirstMidName = "Candace", LastName = "Kapoor", HireDate = DateTime.Parse("2001-01-15"), BirthDate = DateTime.Parse("1975-04-11") },
new Instructor { FirstMidName = "Roger", LastName = "Zheng", HireDate = DateTime.Parse("2004-02-12"), BirthDate = DateTime.Parse("1957-10-12") }
};
在ContosoUniversity项目打开Instructors.aspx文件，添加一个模板字段来显示birth date，在hire date和office assignment字段之间：
<asp:TemplateField HeaderText="Birth Date" SortExpression="BirthDate">
<ItemTemplate>
<asp:Label ID="InstructorBirthDateLabel" runat="server" Text='<%# Eval("BirthDate", "{0:d}") %>'></asp:Label>
</ItemTemplate>
<EditItemTemplate>
<asp:TextBox ID="InstructorBirthDateTextBox" runat="server" Text='<%# Bind("BirthDate", "{0:d}") %>'
Width="7em"></asp:TextBox>
</EditItemTemplate>
</asp:TemplateField>
（注：如果代码变形了，可以通过CTRL+K+D来格式化代码）
在Students.aspx文件，在enrollment date 之前添加一个dynamic字段显示birth date:
<asp:DynamicField DataField="BirthDate" HeaderText="Birth Date" SortExpression="BirthDate"/>
在StudentsAdd.aspx页面, enrollment date之前添加一个bound字段显示birth date：
<asp:BoundField DataField="BirthDate" HeaderText="Birth Date"
SortExpression="BirthDate"/>
在BLL\SchoolBL.cs文件， 支持按列排序的GetStudents 方法力的switch语句里的default语句之前，添加一个case分支以支持使用birth date排序：
case "BirthDate":
students = students.OrderBy(s => s.BirthDate);
break;
case "BirthDate DESC":
students = students.OrderByDescending(s => s.BirthDate);
break;
运行程序访问Students页面，你可能感觉有一点慢，那是因为Entity Framework探测到了model变了，需要删除并重建数据库，然后将初始化里的数据插入到数据库。页面加载以后，可以看到有了一个birth date新列。
访问Add Students和Instructors页面验证是否有这个新列。
