protected override void OnModelCreating(ModelBuilder modelBuilder) { modelBuilder .Entity<Blog>() .HasOne(e => e.Owner) .WithOne(e => e.OwnedBlog) .OnDelete(DeleteBehavior.ClientCascade); } Now what happens if we load both a person and the blog they own, then delete the person?using va...
OnDelete(DeleteBehavior.ClientCascade)是 Entity Framework Core 中的一个特性,用于定义当关联的实体被删除时,如何处理当前实体的行为。DeleteBehavior.ClientCascade表示当关联的实体被客户端删除时,当前实体也会被删除。 如果你发现OnDelete(DeleteBehavior.ClientCascade)没有删除实体条目,可能是以下...
一个约定,用于将所需外键和ClientSetNull可选外键的删除行为Cascade设置为 。C# 复制 public class CascadeDeleteConvention : Microsoft.EntityFrameworkCore.Metadata.Conventions.IForeignKeyAddedConvention, Microsoft.EntityFrameworkCore.Metadata.Conventions.IForeignKeyRequirednessChangedConvention...
EF Core的Where方法返回的是IQueryable类型,DbSet也实现了IQueryable接口。IQueryable有扩展方法ToQueryString()可以获得SQL,不需要真的执行查询才获取SQL语句。注意:只能获取查询操作的。//注意:引入命名空间 using Microsoft.EntityFrameworkCore; using(PandaDbContext db = new PandaDbContext()) { //获得查询的SQL...
CascadeDeleteEventData.State 属性 参考 反馈 定义 命名空间: Microsoft.EntityFrameworkCore.Diagnostics 程序集: Microsoft.EntityFrameworkCore.dll 包: Microsoft.EntityFrameworkCore v8.0.0 子级正在转换到的状态,通常为“已删除”。 C# 复制 public virtual Microsoft.EntityFrameworkCore.EntityState S...
EntityFramework6.X 之Index/Cascade Delete Index 可以通过配置索引,提高查询效率 Cascade Delete 若是设置了级联删除,则在删除主体实体的时候,依赖实体将会自动删除或者设置为空,级联删除可以使用在1对1(0),1对多,多对多的关系中。默认情况下EF是自动开启级联删除,但也可以手动关闭...
Microsoft.EntityFrameworkCore.dll 包: Microsoft.EntityFrameworkCore v9.0.0 Source: CoreLoggerExtensions.cs CascadeDelete事件的日志。 C# publicstaticvoidCascadeDelete(thisMicrosoft.EntityFrameworkCore.Diagnostics.IDiagnosticsLogger<Microsoft.EntityFrameworkCore.DbLoggerCategory.Update> diagnostics, Microsoft.Enti...
Using Entity Framework Core 6.0.1 The following code should create a Module model with the HelpCard Foreign Key set, then set the Help Card Foreign Key to Null and save the model to the database, but instead the Cascade Delete is being triggered and the record is deleted from the databas...
在Entity Framework(EF)中,.WillCascadeOnDelete(false)用于禁止级联删除。它的等价物是Fluent API中的.HasRequired().WithRequiredDependent()。 EF是一个用于.NET开发的对象关系映射(ORM)框架,它提供了将对象模型映射到数据库中的功能。.WillCascadeOnDelete(false)用于指定在删除父实体时是否级联删除子实体。...
The Entity Framework Core Fluent APIOnDeletemethod is used to specify the action which should take place on a dependent entity in a relationship when the principal is deleted. TheOnDeletemethod takes aDeleteBehaviorenum as a parameter: Cascade- dependents should be deleted ...