netorm|大数据导航

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.NET ORM 新概念导航

今天这篇文章分享一款好用简单的ORM框架 SqlSugar ，相比 EF Core的导航查询 更加简单 ，配置更加容易，几分钟就能上手

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 ，相比 其他 .NET ORM语法要简单的多

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 ORM

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; } [Navigate(NavigateType.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; } [Navigate(NavigateType.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; } [Navigate(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; } [Navigate(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Countvar 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 ，.NET 中轻松多级查询

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、ORM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 、.NET ORM 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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