我想先禁用带有实体框架代码的链接表的级联删除.例如,如果许多用户有许多角色,而我试图删除一个角色,我希望阻止该删除,因为当前没有与该角色关联的用户.我已经在我的OnModelCreating
页中删除了级联删除约定:
protected override void OnModelCreating(DbModelBuilder modelBuilder) {
...
modelBuilder.Conventions.Remove<OneToManyCascadeDeleteConvention>();
然后我设置了用户角色链接表:
modelBuilder.Entity<User>()
.HasMany(usr => usr.Roles)
.WithMany(role => role.Users)
.Map(m => {
m.ToTable("UsersRoles");
m.MapLeftKey("UserId");
m.MapRightKey("RoleId");
});
然而,当EF创建数据库时,它会为外键关系创建一个删除级联,例如.
ALTER TABLE [dbo].[UsersRoles] WITH CHECK ADD CONSTRAINT [FK_dbo.UsersRoles_dbo.User_UserId] FOREIGN KEY([UserId])
REFERENCES [dbo].[User] ([UserId])
ON DELETE CASCADE
GO
ALTER TABLE [dbo].[UsersRoles] WITH CHECK ADD CONSTRAINT [FK_dbo.UsersRoles_dbo.Role_RoleId] FOREIGN KEY([RoleId])
REFERENCES [dbo].[Role] ([RoleId])
ON DELETE CASCADE
GO
如何停止EF生成此删除级联?