EF Code First 入门包括数据迁移

创建三个类,第三个类是 EF的上下文

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace EF_CODEFIRST_Test
{
    class GreadInfo
    {
        [Key]
        public int id { get; set; }
        [StringLength(32)] //长度
        [Required]
        public string number { get; set; }
        [Required]
        public DateTime createTime { get; set; }

        public virtual ICollection<Student> Student {get;set;}
}
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.ComponentModel.DataAnnotations;

namespace EF_CODEFIRST_Test
{
    class Student
    {
        [Key]
        public int id { get; set; }
        [Required]
        public string number { get; set; }
        [Required]
        public string name { get; set; }
        [Required]
        public int age { get; set; }
        [Required]
        public DateTime birthday { get; set; }

        public virtual GreadInfo GreadInfo { get;set;}
    }
}

using System;
using System.Collections.Generic;
using System.Data.Entity;
using System.Data.Entity.ModelConfiguration.Conventions;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace EF_CODEFIRST_Test
{
    class CodeFirstDBContext:DbContext
    {
        public CodeFirstDBContext():base("name=ZQDBTestEntities")
        {

        }

        //模型映射成表的时候这个方法被执行
        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();  //将映射成的表移除复数约定，不加s
        }

        //定义俩个属性表示可以对实体进行操作
        public DbSet<GreadInfo> GreadInfo { get; set; }
        public DbSet<Student> Student { get; set; }

    }
}

添加应用程序配置文件 App.config

添加链接字符串,与上下文中对应的一样

安装包 EntityFramework 添加引用 entity

在p'rogram.cs 中使用

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace EF_CODEFIRST_Test
{
    class Program
    {
        static void Main(string[] args)
        {
            CodeFirstDBContext dbContext = new CodeFirstDBContext();
            dbContext.Database.CreateIfNotExists();// 没有就创建DB
            Student s = new Student();
            s.id = 1;
            //s.name = "张三";
            //s.number = "3452";
            //s.age = 15;
            //s.birthday = DateTime.Now.AddYears(-15);
            GreadInfo g = new GreadInfo();
            g.id = 1;
            g.number = "01";
            g.createTime= DateTime.Now.AddYears(-30);
            dbContext.GreadInfo.Add(g);
            var i=dbContext.SaveChanges();
            Console.WriteLine(i);
            Console.ReadKey();
        }
    }
}

数据迁移

第一步：打开NuGet控制台，输入"Enable-Migrations"启用Code First迁移。.