级联保存

nicye2020年10月16日大约 5 分钟约 1419 字

级联保存

接下来的内容，严重依赖【导航属性】的正确配置，请先学会再继续向下！

Topic：文章表
Category：分类表
Comment：评论表
Tag：标签表
ManyToOne（多对一）：Topic（多个）关联 Category（一个）；
OneToOne（一对一）：Topic（一个）关联 Content（一个）；
OneToMany（一对多：Topic（一个）关联 Comment（多个）；
ManyToMany（多对多）：Topic（多个）关联 Tag（多个）；

ManyToOne（多对一）不适合做级联保存，保存 Topic 的时候把 Category 也保存，显然不合理（思考原因），自下向上保存的功能太不可控了。因此下面只讲 OneToOne/OneToMany/ManyToMany 级联保存。

若以上内容不能理解，请多看几遍！

开启功能

.NET CLI

 dotnet add package FreeSql.DbContext

.NET Framework

Install-Package FreeSql.DbContext

本功能 2019 年实现的（稳定），可移步了解 2022 年新发布的《聚合根仓储》（级联更自动）

仓储默认关闭了级联功能，需要手工开启：

repo.DbContextOptions.EnableCascadeSave = true;

机制规则

1、OneToOne 级联保存

v3.2.606+ 支持，并且支持级联删除功能

2、OneToMany 追加或更新子表，不删除子表已存在的数据

repo.Insert(topic);

不删除 Comment 子表已存在的数据
当 topic.Comments 属性为 Empty 时，不做任何操作
保存 topic.Comments 的时候，还会保存 topic.Comments[0-..] 的下级集合属性，向下 18 层

向下 18 层的意思，比如【文章】表，下面有集合属性【评论】，【评论】下面有集合属性【子评论】。

保存【文章】表对象的时候，他会向下检索出集合属性【评论】，然后如果【评论】被保存的时候，再继续向下检索出集合属性【子评论】。一起做 InsertOrUpdate 操作。

3、ManyToMany 完整对比保存中间表，外部表只追加不更新

完整对比保存中间表，对比【多对多】中间表已存在的数据，计算出添加、修改、删除执行。

示例

测试 1：追加保存 OneToMany


class Cagetory
{
    public Guid Id { get; set; }
    public string Name { get; set; }

    public Guid ParentId { get; set; }
    [Navigate(nameof(ParentId))]
    public List<Cagetory> Childs { get; set; }
}
public void TestOneToManyParent()
{
    var repo = fsql.GetRepository<Cagetory>();
    repo.DbContextOptions.EnableCascadeSave = true;
    var cts = new[]
    {
        new Cagetory
        {
            Name = "分类1",
            Childs = new List<Cagetory>(new[]
            {
                new Cagetory { Name = "分类1_1" },
                new Cagetory { Name = "分类1_2" },
                new Cagetory { Name = "分类1_3" }
            })
        },
        new Cagetory
        {
            Name = "分类2",
            Childs = new List<Cagetory>(new[]
            {
                new Cagetory { Name = "分类2_1" },
                new Cagetory { Name = "分类2_2" }
            })
        }
    };
    repo.Insert(cts);
    //执行创建表，和插入数据：
    //INSERT INTO "Cagetory"("Id", "Name", "ParentId") VALUES('5d90afcb-ed57-f6f4-0082-cb6b78eaaf9f', '分类1', '00000000-0000-0000-0000-000000000000'), ('5d90afcb-ed57-f6f4-0082-cb6c5b531b3e', '分类2', '00000000-0000-0000-0000-000000000000')
    //INSERT INTO "Cagetory"("Id", "Name", "ParentId") VALUES('5d90afcb-ed57-f6f4-0082-cb6d0c1c5f1a', '分类1_1', '5d90afcb-ed57-f6f4-0082-cb6b78eaaf9f'), ('5d90afcb-ed57-f6f4-0082-cb6e74bd8eef', '分类1_2', '5d90afcb-ed57-f6f4-0082-cb6b78eaaf9f'), ('5d90afcb-ed57-f6f4-0082-cb6f6267cc5f', '分类1_3', '5d90afcb-ed57-f6f4-0082-cb6b78eaaf9f'), ('5d90afcb-ed57-f6f4-0082-cb7057c41d46', '分类2_1', '5d90afcb-ed57-f6f4-0082-cb6c5b531b3e'), ('5d90afcb-ed57-f6f4-0082-cb7156e0375e', '分类2_2', '5d90afcb-ed57-f6f4-0082-cb6c5b531b3e')
    cts[0].Name = "分类11";
    cts[0].Childs.Clear();
    cts[1].Name = "分类22";
    cts[1].Childs.Clear();
    repo.Update(cts);
    //UPDATE "Cagetory" SET "Name" = CASE "Id"
    //WHEN '5d90afcb-ed57-f6f4-0082-cb6b78eaaf9f' THEN '分类11'
    //WHEN '5d90afcb-ed57-f6f4-0082-cb6c5b531b3e' THEN '分类22' END
    //WHERE ("Id" IN ('5d90afcb-ed57-f6f4-0082-cb6b78eaaf9f','5d90afcb-ed57-f6f4-0082-cb6c5b531b3e'))
    //Childs.Clear 后没有执行删除子集合操作，说明没有做完整的对比
    cts[0].Name = "分类111";
    cts[0].Childs.Clear();
    cts[0].Childs.Add(new Cagetory { Name = "分类1_33" });
    cts[1].Name = "分类222";
    cts[1].Childs.Clear();
    cts[1].Childs.Add(new Cagetory { Name = "分类2_22" });
    repo.Update(cts);
    //UPDATE "Cagetory" SET "Name" = CASE "Id"
    //WHEN '5d90afcb-ed57-f6f4-0082-cb6b78eaaf9f' THEN '分类111'
    //WHEN '5d90afcb-ed57-f6f4-0082-cb6c5b531b3e' THEN '分类222' END
    //WHERE ("Id" IN ('5d90afcb-ed57-f6f4-0082-cb6b78eaaf9f','5d90afcb-ed57-f6f4-0082-cb6c5b531b3e'))
    //INSERT INTO "Cagetory"("Id", "Name", "ParentId") VALUES('5d90afe8-ed57-f6f4-0082-cb725df546ea', '分类1_33', '5d90afcb-ed57-f6f4-0082-cb6b78eaaf9f'), ('5d90afe8-ed57-f6f4-0082-cb7338a6214c', '分类2_22', '5d90afcb-ed57-f6f4-0082-cb6c5b531b3e')
}

测试 2：完整保存 ManyToMany

class Song
{
    public Guid Id { get; set; }
    public string Name { get; set; }
    public List<Tag> Tags { get; set; }
}
class Tag
{
    public Guid Id { get; set; }
    public string TagName { get; set; }
    public List<Song> Songs { get; set; }
}
class SongTag
{
    public Guid SongId { get; set; }
    public Song Song { get; set; }
    public Guid TagId { get; set; }
    public Tag Tag { get; set; }
}

[Fact]
public void TestManyToMany()
{
    var tags = new[]
    {
        new Tag { TagName = "流行" },
        new Tag { TagName = "80后" },
        new Tag { TagName = "00后" },
        new Tag { TagName = "摇滚" }
    };
    var ss = new[]
    {
        new Song
        {
            Name = "爱你一万年.mp3",
            Tags = new List<Tag>(new[]
            {
                tags[0], tags[1]
            })
        },
        new Song
        {
            Name = "李白.mp3",
            Tags = new List<Tag>(new[]
            {
                tags[0], tags[2]
            })
        }
    };
    var repo = fsql.GetRepository<Song>();
    repo.DbContextOptions.EnableCascadeSave = true;
    repo.Insert(ss);
    //INSERT INTO "Song"("Id", "Name") VALUES('5d90fdb3-6a6b-2c58-00c8-37974177440d', '爱你一万年.mp3'), ('5d90fdb3-6a6b-2c58-00c8-37987f29b197', '李白.mp3')
    //INSERT INTO "Tag"("Id", "TagName") VALUES('5d90fdb7-6a6b-2c58-00c8-37991ead4f05', '流行'), ('5d90fdbd-6a6b-2c58-00c8-379a0432a09c', '80后')
    //INSERT INTO "SongTag"("SongId", "TagId") VALUES('5d90fdb3-6a6b-2c58-00c8-37974177440d', '5d90fdb7-6a6b-2c58-00c8-37991ead4f05'), ('5d90fdb3-6a6b-2c58-00c8-37974177440d', '5d90fdbd-6a6b-2c58-00c8-379a0432a09c')
    //INSERT INTO "Tag"("Id", "TagName") VALUES('5d90fdcc-6a6b-2c58-00c8-379b5af59d25', '00后')
    //INSERT INTO "SongTag"("SongId", "TagId") VALUES('5d90fdb3-6a6b-2c58-00c8-37987f29b197', '5d90fdb7-6a6b-2c58-00c8-37991ead4f05'), ('5d90fdb3-6a6b-2c58-00c8-37987f29b197', '5d90fdcc-6a6b-2c58-00c8-379b5af59d25')

    ss[0].Name = "爱你一万年.mp5";
    ss[0].Tags.Clear();
    ss[0].Tags.Add(tags[0]);
    ss[1].Name = "李白.mp5";
    ss[1].Tags.Clear();
    ss[1].Tags.Add(tags[3]);
    repo.Update(ss);
    //UPDATE "Song" SET "Name" = CASE "Id"
    //WHEN '5d90fdb3-6a6b-2c58-00c8-37974177440d' THEN '爱你一万年.mp5'
    //WHEN '5d90fdb3-6a6b-2c58-00c8-37987f29b197' THEN '李白.mp5' END
    //WHERE ("Id" IN ('5d90fdb3-6a6b-2c58-00c8-37974177440d','5d90fdb3-6a6b-2c58-00c8-37987f29b197'))

    //SELECT a."SongId", a."TagId"
    //FROM "SongTag" a
    //WHERE (a."SongId" = '5d90fdb3-6a6b-2c58-00c8-37974177440d')

    //DELETE FROM "SongTag" WHERE ("SongId" = '5d90fdb3-6a6b-2c58-00c8-37974177440d' AND "TagId" = '5d90fdbd-6a6b-2c58-00c8-379a0432a09c')
    //INSERT INTO "Tag"("Id", "TagName") VALUES('5d90febd-6a6b-2c58-00c8-379c21acfc72', '摇滚')

    //SELECT a."SongId", a."TagId"
    //FROM "SongTag" a
    //WHERE (a."SongId" = '5d90fdb3-6a6b-2c58-00c8-37987f29b197')

    //DELETE FROM "SongTag" WHERE ("SongId" = '5d90fdb3-6a6b-2c58-00c8-37987f29b197' AND "TagId" = '5d90fdb7-6a6b-2c58-00c8-37991ead4f05' OR "SongId" = '5d90fdb3-6a6b-2c58-00c8-37987f29b197' AND "TagId" = '5d90fdcc-6a6b-2c58-00c8-379b5af59d25')
    //INSERT INTO "SongTag"("SongId", "TagId") VALUES('5d90fdb3-6a6b-2c58-00c8-37987f29b197', '5d90febd-6a6b-2c58-00c8-379c21acfc72')

    ss[0].Name = "爱你一万年.mp4";
    ss[0].Tags.Clear();
    ss[1].Name = "李白.mp4";
    ss[1].Tags.Clear();
    repo.Update(ss);
    //DELETE FROM "SongTag" WHERE ("SongId" = '5d90fdb3-6a6b-2c58-00c8-37974177440d')
    //DELETE FROM "SongTag" WHERE ("SongId" = '5d90fdb3-6a6b-2c58-00c8-37987f29b197')

    //UPDATE "Song" SET "Name" = CASE "Id"
    //WHEN '5d90fdb3-6a6b-2c58-00c8-37974177440d' THEN '爱你一万年.mp4'
    //WHEN '5d90fdb3-6a6b-2c58-00c8-37987f29b197' THEN '李白.mp4' END
    //WHERE ("Id" IN ('5d90fdb3-6a6b-2c58-00c8-37974177440d','5d90fdb3-6a6b-2c58-00c8-37987f29b197'))
}