code first 创建数据库

CodeFirst 用中文说是代码优先，此技术可以让我们先写代码，然后由Entity Framework根据我们的代码建立数据库

接下来用学生这个例子来演示，有学生表，课程表，和成绩表三张表

首先是Model层

fee_item

public class fee_item : feemodel
    {
        public fee_item()
        {
            type = feeItemType.Normal;
        }

[Required]
        [StringLength(16, MinimumLength = 2)]
        public string name { get; set; }//缴费类型

[Required]
        [StringLength(16, MinimumLength = 8)]
        public string code { get; set; }

public feeItemType type { get; set; }

public bool State { get; set; }//是否启用
    }

[Key]表示在数据库中该字段为主键，[Required]表示不为空，[StringLength]也就是长度了

这一步完成之后，我们要建立一个StudentInfoEntities的类，这个类要继承自DbContext,而DbContext类在System.Data.Entity命名空间下，需引用EntityFramework.dll类库，

如安装不了，可以去Visual Studio Gallery下载，其实，只需要引用一个叫做Entity Framework的dll类库即可

FeeDbContext类

public FeeDbContext() : base("FeeDbContext") { }//base("FeeDbContext")连接数据库

public DbSet<organization> organization { get; set; }
        public DbSet<org_fee> org_fee { get; set; }
        public DbSet<fee_item> fee_item { get; set; }
        public DbSet<item_fee_time> item_fee_time { get; set; }
        public DbSet<bill_power> bill_power { get; set; }
        public DbSet<bill_net> bill_net { get; set; }
        public DbSet<bill_cet46> bill_cet46 { get; set; }
        public DbSet<bill_insurance> bill_insurance { get; set; }
        public DbSet<bill_tuition> bill_tuition { get; set; }

protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            base.OnModelCreating(modelBuilder);
            modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
            //modelBuilder.Ignore<LookupSignType>();
        }

可以加一些默认值进去

        public void Initialize(FeeDbContext context)
        {
            List<dept> depts = new List<dept>() {
                new dept(){oid=1, name="新中新集团", state=true},
                new dept(){oid=2, name="山东大学", state=true},
                new dept(){oid=3, name="浙江大学", state=true},
                new dept(){oid=4, name="同济大学", state=true}
            };
            List<organization> orgs = new List<organization>() {
                new organization(){oid=1, name="新中新集团", state=true},
                new organization(){oid=2, name="山东大学", state=true},
                new organization(){oid=3, name="浙江大学", state=true},
                new organization(){oid=4, name="同济大学", state=true}
            };

            //depts.ForEach(o => context.dept.Add(o));
            orgs.ForEach(o => context.organization.Add(o));
            context.SaveChanges();
        }

最后

public void Build()
        {
            try
            {
                var context = new FeeDbContext();
                if (!context.Database.Exists())
                {
                    new List<IDataInitializer<FeeDbContext>>() { 
                        new DataInit4dept()
                    }.Setup<FeeDbContext>(context);
                }
            }
            catch (Exception e)
            {
                Console.WriteLine("数据库初始化报错：" + e.Message);
                throw e;
            }
        }

点击调试，触发一下，查看数据库