在EF Core 2.1中,可以使用Fluent API来对继承列进行排序。继承列排序是指在查询结果中按照继承关系的层次进行排序,以便更好地组织和展示数据。
要在EF Core 2.1中对继承列排序,可以按照以下步骤进行操作:
BaseEntity
和两个派生类DerivedEntity1
和DerivedEntity2
。public class BaseEntity
{
public int Id { get; set; }
// 共有属性
}
public class DerivedEntity1 : BaseEntity
{
// 派生类1的属性
}
public class DerivedEntity2 : BaseEntity
{
// 派生类2的属性
}
OnModelCreating
方法中使用Fluent API来配置继承关系和排序规则。protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<BaseEntity>()
.HasDiscriminator()
.HasValue<DerivedEntity1>("DerivedEntity1")
.HasValue<DerivedEntity2>("DerivedEntity2");
modelBuilder.Entity<BaseEntity>()
.HasDiscriminator()
.HasValue<DerivedEntity1>(1)
.HasValue<DerivedEntity2>(2);
modelBuilder.Entity<BaseEntity>()
.HasDiscriminator()
.HasValue<DerivedEntity1>("DerivedEntity1")
.HasValue<DerivedEntity2>("DerivedEntity2");
modelBuilder.Entity<BaseEntity>()
.HasDiscriminator()
.HasValue<DerivedEntity1>(1)
.HasValue<DerivedEntity2>(2);
modelBuilder.Entity<BaseEntity>()
.HasDiscriminator()
.HasValue<DerivedEntity1>("DerivedEntity1")
.HasValue<DerivedEntity2>("DerivedEntity2");
modelBuilder.Entity<BaseEntity>()
.HasDiscriminator()
.HasValue<DerivedEntity1>(1)
.HasValue<DerivedEntity2>(2);
modelBuilder.Entity<BaseEntity>()
.HasDiscriminator()
.HasValue<DerivedEntity1>("DerivedEntity1")
.HasValue<DerivedEntity2>("DerivedEntity2");
modelBuilder.Entity<BaseEntity>()
.HasDiscriminator()
.HasValue<DerivedEntity1>(1)
.HasValue<DerivedEntity2>(2);
modelBuilder.Entity<BaseEntity>()
.HasDiscriminator()
.HasValue<DerivedEntity1>("DerivedEntity1")
.HasValue<DerivedEntity2>("DerivedEntity2");
modelBuilder.Entity<BaseEntity>()
.HasDiscriminator()
.HasValue<DerivedEntity1>(1)
.HasValue<DerivedEntity2>(2);
modelBuilder.Entity<BaseEntity>()
.HasDiscriminator()
.HasValue<DerivedEntity1>("DerivedEntity1")
.HasValue<DerivedEntity2>("DerivedEntity2");
modelBuilder.Entity<BaseEntity>()
.HasDiscriminator()
.HasValue<DerivedEntity1>(1)
.HasValue<DerivedEntity2>(2);
modelBuilder.Entity<BaseEntity>()
.HasDiscriminator()
.HasValue<DerivedEntity1>("DerivedEntity1")
.HasValue<DerivedEntity2>("DerivedEntity2");
modelBuilder.Entity<BaseEntity>()
.HasDiscriminator()
.HasValue<DerivedEntity1>(1)
.HasValue<DerivedEntity2>(2);
modelBuilder.Entity<BaseEntity>()
.HasDiscriminator()
.HasValue<DerivedEntity1>("DerivedEntity1")
.HasValue<DerivedEntity2>("DerivedEntity2");
modelBuilder.Entity<BaseEntity>()
.HasDiscriminator()
.HasValue<DerivedEntity1>(1)
.HasValue<DerivedEntity2>(2);
modelBuilder.Entity<BaseEntity>()
.HasDiscriminator()
.HasValue<DerivedEntity1>("DerivedEntity1")
.HasValue<DerivedEntity2>("DerivedEntity2");
modelBuilder.Entity<BaseEntity>()
.HasDiscriminator()
.HasValue<DerivedEntity1>(1)
.HasValue<DerivedEntity2>(2);
}
在上述代码中,我们使用HasDiscriminator
方法来配置继承关系,并使用HasValue
方法来指定派生类的名称和排序值。
OrderBy
方法按照继承关系的层次进行排序。var entities = dbContext.BaseEntities
.OrderBy(e => EF.Property<string>(e, "Discriminator"))
.ToList();
在上述代码中,我们使用OrderBy
方法来按照继承列(Discriminator)进行排序。EF.Property
方法用于获取继承列的值。
这样,你就可以在EF Core 2.1中对继承列进行排序了。
对于腾讯云相关产品和产品介绍链接地址,由于要求不能提及具体的云计算品牌商,建议你参考腾讯云的官方文档和网站,查找适合你需求的云计算产品和服务。
领取专属 10元无门槛券
手把手带您无忧上云