EF CoreEF core中使用FluentAPI对外键进行指定配置

Posted 2020-12-13 C_supreme

有两个实体，关系如下：

public class CatalogNodeEntity : FullAuditedEntity<Guid>, IMultiTenant
    {
public virtual string Name { get; protected set; }
        
        public virtual string DisplayName { get; protected set; }

        private List<CatalogLayerEntity> Layers = new List<CatalogLayerEntity>();
    }

public class CatalogLayerEntity:FullAuditedEntity<Guid>, IMultiTenant
    {

        public virtual string Name { get; protected set; }

        public virtual Guid? CatalogNodeId { get; set; }
        
        public virtual CatalogNodeEntity CatalogNode { get; set; }

     }

配置one to many 的实体关系，可这样配置

builder.Entity<CatalogNodeEntity>(m =>
            {
                m.ToTable(options.TablePrefix + "CatalogNode", options.Schema);
                m.ConfigureByConvention();
                m.Property(o => o.Name).IsRequired().HasMaxLength(CatalogConsts.MaxNameLength);
                m.HasMany(u => u.Layers).WithOne(u=>u.CatalogNode).HasForeignKey(u=>u.CatalogNodeId).OnDelete(DeleteBehavior.Cascade);
            });

这里有个坑需要注意，如果在WithOne的函数中没有指定实体，又在HasForeignKey中指定了外键，这是进行Migration就会出现两个外键

m.HasMany(u => u.Layers).WithOne().HasForeignKey(u=>u.CatalogNodeId).OnDelete(DeleteBehavior.Cascade);