实体框架4.1代码数据库中的第一个永久表

问题描述：

我有一张表，可以永久保存美国邮政编码和城市名称列表。不幸的是，似乎在EF 4.1中，如果我在开发过程中修改模型，整个数据库需要被删除并重新创建。由于EF中尚未支持迁移，这似乎是一个问题。任何想法？

I have an table that permanently stores a list of zip codes and city names for the US. Unfortunately, it seems that with EF 4.1 if I modify the model during developement, the entire db needs to be droped and recreated. Since migrations are not yet supported in EF, this seems to be a problem. Any ideas?

答

您可以使用custome初始化程序类。在这里，您可以在数据库更改发生时插入所有值。这是来自msdn的Contoso Universty示例。

you can use a custome initializer class. In here you can insert all values when database changes happens. This is from Contoso Universty example from msdn.

    public class SchoolInitializer : DropCreateDatabaseIfModelChanges<SchoolContext>
        {
            protected override void Seed(SchoolContext context)
            {
                var students = new List<Student>
                {
                    new Student { FirstMidName = "Carson",   LastName = "Alexander", EnrollmentDate = DateTime.Parse("2005-09-01") },
                    new Student { FirstMidName = "Meredith", LastName = "Alonso",    EnrollmentDate = DateTime.Parse("2002-09-01") },
                    new Student { FirstMidName = "Arturo",   LastName = "Anand",     EnrollmentDate = DateTime.Parse("2003-09-01") },
                    new Student { FirstMidName = "Gytis",    LastName = "Barzdukas", EnrollmentDate = DateTime.Parse("2002-09-01") },
                    new Student { FirstMidName = "Yan",      LastName = "Li",        EnrollmentDate = DateTime.Parse("2002-09-01") },
                    new Student { FirstMidName = "Peggy",    LastName = "Justice",   EnrollmentDate = DateTime.Parse("2001-09-01") },
                    new Student { FirstMidName = "Laura",    LastName = "Norman",    EnrollmentDate = DateTime.Parse("2003-09-01") },
                    new Student { FirstMidName = "Nino",     LastName = "Olivetto",  EnrollmentDate = DateTime.Parse("2005-09-01") }
                };
                students.ForEach(s => context.Students.Add(s));
                context.SaveChanges();


    }
 }

实体框架4.1代码数据库中的第一个永久表

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