update

_Sidebar.md

@@ -25,6 +25,7 @@
 * [仓储层](Repository) [Repository Layer](Repository-Layer)
     * [工作单元](%e5%b7%a5%e4%bd%9c%e5%8d%95%e5%85%83) [Unit of Work](Unit-of-Work)
     * [联级保存](%e8%81%94%e7%ba%a7%e4%bf%9d%e5%ad%98) [Cascade Saving](Cascade-Saving)
+    * [联级删除](%E8%81%94%E7%BA%A7%E5%88%A0%E9%99%A4)
     * [工作单元管理器](DI-UnitOfWorkManager事务) [UoW Manager](Unit-of-Work-Manager)
 * [DbContext](DbContext)
 * [CodeFirst](CodeFirst)

联级删除.md

@@ -0,0 +1,83 @@
+## 基于【对象】级联删除
+
+> 比如 Include/IncludeMany 查询的对象，可以使用此方法级联删除它们。
+
+```c#
+var repo = fsql.GetRepository<Group>();
+repo.DbContextOptions.EnableCascadeSave = true; //关键设置
+repo.Insert(new UserGroup
+{
+    GroupName = "group01",
+    Users = new List<User>
+    {
+        new User { Username = "admin01", Password = "pwd01", UserExt = new UserExt { Remark = "用户备注01" } },
+        new User { Username = "admin02", Password = "pwd02", UserExt = new UserExt { Remark = "用户备注02" } },
+        new User { Username = "admin03", Password = "pwd03", UserExt = new UserExt { Remark = "用户备注03" } },
+    }
+}); //级联添加测试数据
+//INSERT INTO "usergroup"("groupname") VALUES('group01') RETURNING "id"
+//INSERT INTO "user"("username", "password", "groupid") VALUES('admin01', 'pwd01', 1), ('admin02', 'pwd02', 1), ('admin03', 'pwd03', 1) RETURNING "id" as "Id", "username" as "Username", "password" as "Password", "groupid" as "GroupId"
+//INSERT INTO "userext"("userid", "remark") VALUES(3, '用户备注01'), (4, '用户备注02'), (5, '用户备注03')
+
+var groups = repo.Select
+    .IncludeMany(a => a.Users, 
+        then => then.Include(b => b.UserExt))
+    .ToList();
+repo.Delete(groups); //级联删除，递归向下遍历 group OneToOne/OneToMany/ManyToMany 导航属性
+//DELETE FROM "userext" WHERE ("userid" IN (3,4,5))
+//DELETE FROM "user" WHERE ("id" IN (3,4,5))
+//DELETE FROM "usergroup" WHERE ("id" = 1)
+```
+
+## 基于【数据库】级联删除
+
+> 根据设置的导航属性，递归删除 OneToOne/OneToMany/ManyToMany 对应数据，并返回已删除的数据。此功能不依赖数据库外键
+
+```c#
+var repo = fsql.GetRepository<Group>();
+var ret = repo.DeleteCascadeByDatabase(a => a.Id == 1);
+//SELECT a."id", a."username", a."password", a."groupid" FROM "user" a WHERE (a."groupid" = 1)
+//SELECT a."userid", a."remark" FROM "userext" a WHERE (a."userid" IN (3,4,5))
+//DELETE FROM "userext" WHERE ("userid" IN (3,4,5))
+//DELETE FROM "user" WHERE ("id" IN (3,4,5))
+//DELETE FROM "usergroup" WHERE ("id" = 1)
+
+//ret   Count = 7	System.Collections.Generic.List<object>
+//  [0]	{UserExt}	object {UserExt}
+//  [1]	{UserExt}	object {UserExt}
+//  [2]	{UserExt}	object {UserExt}
+//  [3]	{User}	    object {User}
+//  [4]	{User}	    object {User}
+//  [5]	{User}  	object {User}
+//  [6]	{UserGroup}	object {UserGroup}
+
+public class Group
+{
+    [Column(IsIdentity = true)]
+    public int Id { get; set; }
+    public string GroupName { get; set; }
+
+    [Navigate(nameof(User.GroupId))]
+    public List<User> Users { get; set; }
+}
+public class User
+{
+    [Column(IsIdentity = true)]
+    public int Id { get; set; }
+    public string Username { get; set; }
+    public string Password { get; set; }
+    public int GroupId { get; set; }
+
+    [Navigate(nameof(Id))]
+    public UserExt UserExt { get; set; }
+}
+public class UserExt
+{
+    [Column(IsPrimary = true)]
+    public int UserId { get; set; }
+    public string Remark { get; set; }
+
+    [Navigate(nameof(UserId))]
+    public User User { get; set; }
+}
+```