比较爽的导航查询 功能 – SqlSugar ORM

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摘要

作用:主要处理主对象里面有子对象这种层级关系查询其它ORM导航查询 需要 各种配置或者外键,而SqlSugar则开箱就用,无外键,只需配置特性和主键就能使用


1、导航查询特点

作用:主要处理主对象里面有子对象这种层级关系查询

1.1 无外键开箱就用

其它ORM导航查询 需要 各种配置或者外键,而SqlSugar则开箱就用,无外键,只需配置特性和主键就能使用

1.2 高性能优 

 查询 性能非常强悍  

 支持大数据分页导航查询

3.3 语法超级爽

注意:多级查询时VS有时候没提示直接写就行了

 var list=db.Queryable<Test>()            .Includes(x => x.Provinces,x=>x.Citys ,x=>x.Street)//多级查询 有时候VS没提示手写             .Includes(x => x.ClassInfo)// 一级查询            .ToList();                                      var list=db.Queryable<Test>()         //多级查询  加排序过滤         .Includes(x =>x.Provinces.Where(z=>z.Id>0).OrderBy(z=>z.Id).ToList(),x=>x.Citys,x=>x.Street)          // 一级查询         .Includes(x =>x.ClassInfo)         .ToList(); 

  

2、新导航查询 

适合有主键的常规操作, 请升级到5.0.6.8

2.1 一对一

//实体         public class StudentA         {             [SugarColumn(IsPrimaryKey = true, IsIdentity = true)]             public int StudentId { get; set; }             public string Name { get; set; }             public int SchoolId { get; set; }             [Navigat(NavigatType.OneToOne, nameof(SchoolId))]//一对一             public SchoolA SchoolA { get; set; }            }         public class SchoolA         {             [SugarColumn(IsPrimaryKey = true, IsIdentity = true)]             public int SchoolId { get; set; }             public string SchoolName { get; set; }          } //代码  var list2 = db.Queryable<StudentA>()            .Includes(x => x.SchoolA)            .Where(x => x.SchoolA.SchoolName == "北大")//可以对一级导航进行过滤            .ToList();

2.2 一对多

    public class StudentA     {      [SugarColumn(IsPrimaryKey = true, IsIdentity = true)]      public int StudentId { get; set; }      public string Name { get; set; }      public int SchoolId { get; set; }      [Navigat(NavigatType.OneToMany, nameof(BookA.studenId))]      public List<BookA> Books { get; set; }        }     public class BookA     {        [SugarColumn(IsPrimaryKey = true, IsIdentity = true)]        public int BookId { get; set; }       public string Name { get; set; }       public int studenId { get; set; }     }               //例1: 简单用法     var list = db.Queryable<StudentA>()     .Includes(x => x.Books)     .ToList();           //例2:支持Any和Count 对主表进行过滤     var list = db.Queryable<StudentA>()     .Includes(x => x.Books)      .Where(x=>x.Books.Any(z=>z.BookId==1))     .ToList();           //例3:对子对象进行排序和过滤      var list = db.Queryable<StudentA>()        .Includes(x => x.Books.Where(y=>y.BookId >0).OrderBy(y=>y.BookId ).ToList())         .ToList(); 

  

2.3 多对多

   //多对多        public class ABMapping1        {             [SugarColumn(IsPrimaryKey = true )]             public int AId { get; set; }             [SugarColumn(IsPrimaryKey = true)]             public int BId { get; set; }         }         public class A1         {             [SugarColumn(IsPrimaryKey = true, IsIdentity = true  )]             public int Id { get; set; }             public string Name { get; set; }             [Navigat(typeof(ABMapping1),nameof(ABMapping1.AId),nameof(ABMapping1.BId))]             public List<B1> BList { get; set; }         }         public class B1         {             [SugarColumn(IsPrimaryKey = true , IsIdentity = true)]             public int Id { get; set; }             public string Name { get; set; }             [Navigat(typeof(ABMapping1), nameof(ABMapping1.BId), nameof(ABMapping1.AId))]             public List<A1> AList { get; set; }         }  //例1:简单用法 var list3= db.Queryable<A1>().Includes(x => x.BList).ToList();     //例2:支持子对象排序和过滤 var list3= db.Queryable<A1>().Includes(x => x.BList.Where(z=>z.Id>0).ToList()).ToList();     //例3:支持主表过滤  Any和Count var list3= db.Queryable<A1>().Includes(x => x.BList)                              .Where(x=>x.BList .Any(z=>z.Id ==1)).ToList();

 

2.4 多级查询

配置好实体类,我们可以多级查询

 var list=db.Queryable<Test>()                 .Includes(x => x.Provinces,x=>x.Citys ,x=>x.Street)//有时候没提示 直接写                 .Includes(x => x.ClassInfo)// 一级查询                 .ToList(); 

  

2.5 大数据分页导航 

适合一次性查询1000条以上的导航

  var list = new List<Tree1>();       db.Queryable<Tree1>()         .Includes(it => it.Child)         .ForEach(it => list.Add(it), 300); //每次查询300条 

 更多用法:https://www.donet5.com/Home/Doc?typeId=2414

 

3、无配置映射(高性能)

适合没有主键或者复杂的一些操作

 

 3.1 无配置映射实现二层

结构:  Student->SchoolA

var list = db.Queryable<StudentA>().ToList(); db.ThenMapper(list, stu => {   //如果加Where不能带有stu参数,stu参数写到 SetContext   stu.SchoolA=db.Queryable<SchoolA>().SetContext(scl=>scl.SchoolId,()=>stu.SchoolId,stu).FirstOrDefault(); }); // SetContext不会生成循环操作,高性能  和直接Where性能是不一样的

如果没有SetContext那么这个查询将会循环

3.2  无配置映射无限级

了解原理后我们用ThenMapper想映射哪层就映射哪层

var treeRoot=db.Queryable<Tree>().Where(it => it.Id == 1).ToList(); //第一层 db.ThenMapper(treeRoot, item => {     item.Child = db.Queryable<Tree>().SetContext(x => x.ParentId, () => item.Id, item).ToList(); }); //第二层 db.ThenMapper(treeRoot.SelectMany(it=>it.Child), it => {     it.Child = db.Queryable<Tree>().SetContext(x => x.ParentId, () => it.Id, it).ToList(); }); //第三层 db.ThenMapper(treeRoot.SelectMany(it => it.Child).SelectMany(it=>it.Child), it => {     it.Child = db.Queryable<Tree>().SetContext(x => x.ParentId, () => it.Id, it).ToList(); }); //这儿只是用树型结构来证明可以实现无限级别导航查询 ,实际开发中树型结构用ToTree实现 public class Tree { [SqlSugar.SugarColumn(IsPrimaryKey =true)] public int Id { get; set; } public string Name { get; set; } public int ParentId { get; set; } [SqlSugar.SugarColumn(IsIgnore = true)] public Tree Parent { get; set; } [SqlSugar.SugarColumn(IsIgnore = true)] public List<Tree> Child { get; set; } } // SetContext不会生成循环操作,高性能  和直接Where性能是不一样的

 

4 、未来计划

Json to sql  正在开发中 ,未来将打造一套直接由前端操作数据库的API

 {  "Queryable":"order",   Select:[ [{SqlFunc_AggregateMin:["id"]},"id"], [{SqlFunc_GetDate:[]},"Date"] ]  } 

将支持 权限过滤 ,验证,多表查询,层级导航查询 等  

 

GitHUB 源码:

https://github.com/donet5/SqlSugar

 

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