标签：ssid com 设置 api 依赖 src 保存 key int
1对1、1对0 的关系
例如：Entity1与零个或一个Entity2的实例有关系
public class Student { public Student() { } public int StudentId { get; set; } public string StudentName { get; set; } public virtual StudentAddress Address { get; set; } } public class StudentAddress { public int StudentAddressId { get; set; } public string Address1 { get; set; } public string Address2 { get; set; } public string City { get; set; } public int Zipcode { get; set; } public string State { get; set; } public string Country { get; set; } public virtual Student Student { get; set; } }
在关系型数据库（如SQL Server）中，1对0或1的关系是一个表的主键将是另一个关系表的主键或外键
因此，创建Student表的时候设置StudentId为主键，StudentAddress表的StudentAddressId既是主键有事外键
在Code First默认约定中，StudentId属性默认为Student的主键，StudentAddressId默认为StudentAddress的主键，因此，我们只需要配置StudentAddressId又为外键就行
通过如下配置即可
public class Student { public Student() { } public int StudentId { get; set; } public string StudentName { get; set; } public virtual StudentAddress Address { get; set; } } public class StudentAddress { [ForeignKey("Student")] public int StudentAddressId { get; set; } public string Address1 { get; set; } public string Address2 { get; set; } public string City { get; set; } public int Zipcode { get; set; } public string State { get; set; } public string Country { get; set; } public virtual Student Student { get; set; } }
public class Student { public Student() { } public int StudentId { get; set; } public string StudentName { get; set; } public virtual StudentAddress Address { get; set; } } public class StudentAddress { [Key, ForeignKey("Student")] public int StudentId { get; set; } public string Address1 { get; set; } public string Address2 { get; set; } public string City { get; set; } public int Zipcode { get; set; } public string State { get; set; } public string Country { get; set; } public virtual Student Student { get; set; } }
Fluent API配置
protected override void OnModelCreating(DbModelBuilder modelBuilder) { // Configure Student & StudentAddress entity modelBuilder.Entity<Student>() .HasOptional(s => s.Address) // Mark Address property optional in Student entity .WithRequired(ad => ad.Student); // mark Student property as required in StudentAddress entity. Cannot save StudentAddress without Student }
上面的配置说明：StudentAddress在Student中的导航属性是可选的（没有StudentAddress也可以保存Student），Student在StudentAddress中的导航属性是必须的（没有Student的话StudentAddress保存不了），StudentAddressId作为外键
public class Student { public Student() { } public int StudentId { get; set; } public string StudentName { get; set; } public virtual StudentAddress Address { get; set; } } public class StudentAddress { public int StudentId { get; set; } public string Address1 { get; set; } public string Address2 { get; set; } public string City { get; set; } public int Zipcode { get; set; } public string State { get; set; } public string Country { get; set; } public virtual Student Student { get; set; } }
protected override void OnModelCreating(DbModelBuilder modelBuilder) { // Configure StudentId as PK for StudentAddress modelBuilder.Entity<StudentAddress>() .HasKey(e => e.StudentId); // Configure StudentId as FK for StudentAddress modelBuilder.Entity<Student>() .HasOptional(s => s.Address) .WithRequired(ad => ad.StudentId); }
一对一的关系
一对一在MS SQL Server中在技术上是不可能的，它总是1对0或1的关系，EF是在实体上表现为一对一的关系，而不是在数据库中
protected override void OnModelCreating(DbModelBuilder modelBuilder) { // Configure StudentId as PK for StudentAddress modelBuilder.Entity<StudentAddress>() .HasKey(e => e.StudentId); // Configure StudentId as FK for StudentAddress modelBuilder.Entity<Student>() .HasRequired(s => s.Address) .WithRequiredPrincipal(ad => ad.Student); }
modelBuilder.Entity<Student>().HasRequired(s => s.Address)表明Address属性是必须的
.WithRequiredPrincipal(ad => ad.Student)
注：主实体是Student，依赖实体是StudentAddress
标签：ssid com 设置 api 依赖 src 保存 key int
原文地址：http://www.cnblogs.com/lanpingwang/p/6641650.html
