• EF6 代码优先,根据model类自动建表


    EF代码优先

    新建一个控制台应用程序,代码如下

    控制台代码

    private static void Main(string[] args)
            {
                //SchoolContext:EF6自动建表的类
                using (var ctx = new SchoolContext())
                {
                    //Student表名
                    var student = new Student() { StudentName = "Bill" };
    
                    //给Student表添加数据
                    ctx.Students.Add(student);
    
                    //给Teachers添加数据
                    ctx.Teachers.Add(new Teacher() { TeacherName="嫖老师",ModeOfTeaching= TeachingMode.ClassRoom });
    
                    //保存操作
                    ctx.SaveChanges();
    
                    //EF6查询动作,FirstOrDefault:取序列中满足条件的第一个元素,如果没有元素满足条件,则返回默认值
                    var dStu = ctx.Students.Where(x => x.StudentName == "Bill").FirstOrDefault();
    
                    //删除Students表查出来StudentName = "Bill"的数据
                    ctx.Students.Remove(dStu);
    
                    ctx.SaveChanges();
                    
                }
                Console.WriteLine("Demo completed.");
                Console.ReadLine();
            }
    

    这个是后台代码

    //继承DbContext实现EF6的相关操作
    public class SchoolContext : DbContext
        {
            //构造函数,base里写连接数据库语句
            public SchoolContext() : base("Server=.;uid=sa;pwd=123456;database=EFTest;")
            {
                //数据库不存在时重新创建数据库,避免了新建完库后有再次重复该动作
                Database.SetInitializer<SchoolContext>(new CreateDatabaseIfNotExists<SchoolContext>());//
    
                //输出SQL日志
                Database.Log += PrintSql;
            }
            
            public void PrintSql(string sql)
            {
                Console.WriteLine(sql);
            }
    
            protected override void OnModelCreating(DbModelBuilder modelBuilder)
            {
                //Adds configurations for Student from separate class
    
                //执行StudentConfigurations里的相关配置
                modelBuilder.Configurations.Add(new StudentConfigurations());
    
                //使Teacher这个model新建的表名为TeacherInfo
                modelBuilder.Entity<Teacher>()
                    .ToTable("TeacherInfo");
    
                modelBuilder.Entity<Teacher>()
                    .MapToStoredProcedures();
            }
    
            /// <summary>
            /// 实例化后可以操作下边表的增删改查
            /// </summary>
            public DbSet<Student> Students { get; set; }
            public DbSet<Grade> Grades { get; set; }
            public DbSet<Course> Courses { get; set; }
            public DbSet<Teacher> Teachers { get; set; }
            public DbSet<StudentAddress> StudentAddresses { get; set; }
        }
    

    StudentConfigurations类的配置

    public class StudentConfigurations : EntityTypeConfiguration<Student>
        {
            public StudentConfigurations()
            {
                this.Property(s => s.StudentName)
                    .IsRequired()
                    .HasMaxLength(50);
    
                this.Property(s => s.StudentName)
                    .IsConcurrencyToken();
    
                // Configure a one-to-one relationship between Student & StudentAddress
    
                //StudentAddress类重写了被Student里的StudentAddress(Address)
                //WithRequired后者包含前者一个不为null的实例
                //https://www.cnblogs.com/suizhikuo/p/4742372.html
                this.HasOptional(s => s.Address) // Mark Student.Address property optional (nullable)
                    .WithRequired(ad => ad.Student); // Mark StudentAddress.Student property as required (NotNull).
            }
        }
    

    其中一个model-Student类

     public class Student
        {
            public int StudentID { get; set; }
            public string StudentName { get; set; }
            public DateTime? DateOfBirth { get; set; }//?代表可以为空
            public decimal Height { get; set; }
            public float Weight { get; set; }
            public byte[] RowVersion { get; set; }
    
            //fully defined relationship
            public int? GradeId { get; set; }
    
            public virtual Grade Grade { get; set; }
    
            public virtual StudentAddress Address { get; set; }
            public virtual ICollection<Course> Courses { get; set; }
        }
    

    github源码下载

    https://github.com/entityframeworktutorial/EF6-Code-First-Demo

    EF增删改的操作

    https://www.cnblogs.com/hao-1234-1234/archive/2018/04/09/8760985.html

    EF 通过DataAnnotations配置属性和类型

    https://www.cnblogs.com/GreenLeaves/p/7589350.html

    EF 如何关闭自动检测_MigrationHistory

    https://blog.csdn.net/weixin_30660027/article/details/97224729

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  • 原文地址:https://www.cnblogs.com/Chen-Ru/p/14113125.html
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