比較爽的導航查詢 功能 .NET ORM / SqlSugar
阿新 • • 發佈：2022-05-08
.NET ORM 新概念導航
今天這篇文章分享一款好用簡單的ORM框架 SqlSugar ，相比 EF Core的導航查詢 更加簡單 ，配置更加容易，幾分鐘就能上手
1、導航查詢特點
作用：主要處理主物件裡面有子物件這種層級關係查詢
1.1 無外來鍵開箱就用
其它ORM導航查詢 需要 各種配置或者外來鍵，而SqlSugar則開箱就用，無外來鍵，只需配置特性和主鍵就能使用
1.2 高效能優
查詢 效能非常強悍
支援大資料分頁導航查詢
3.3 語法超級爽
注意：多級查詢時VS有時候沒提示直接寫就行了 ，相比 其他 .NET ORM語法要簡單的多
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var list=db.Queryable<Test>()
.Includes(x => x.Provinces,x=>x.Citys ,x=>x.Street)//多級查詢 有時候VS沒提示手寫
.Includes(x => x.ClassInfo)// 一級查詢
.ToList();
var list=db.Queryable<Test>()
//多級查詢 加排序過濾
.Includes(x =>x.Provinces.Where(z=>z.Id>0).OrderBy(z=>z.Id).ToList(),x=>x.Citys,x=>x.Street)
// 一級查詢
.Includes(x =>x.ClassInfo)
.ToList();
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2、新導航查詢 ORM
適合有主鍵的常規操作, 請升級到5.0.6.8
2.1 一對一
//實體
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))]//一對一
public SchoolA SchoolA { get; set; }
}
public class SchoolA
{
[SugarColumn(IsPrimaryKey = true, IsIdentity = true)]
public int SchoolId { get; set; }
public string SchoolName { get; set; }
}
//程式碼
var list2 = db.Queryable<StudentA>()
.Includes(x => x.SchoolA)
.Where(x => x.SchoolA.SchoolName == "北大")//可以對一級導航進行過濾
.ToList();2.2 一對多
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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: 簡單用法
var list = db.Queryable<StudentA>()
.Includes(x => x.Books)
.ToList();
//例2:支援Any和Count 對主表進行過濾
var list = db.Queryable<StudentA>()
.Includes(x => x.Books)
.Where(x=>x.Books.Any(z=>z.BookId==1))
.ToList();
//例3:對子物件進行排序和過濾
var list = db.Queryable<StudentA>()
.Includes(x => x.Books.Where(y=>y.BookId >0).OrderBy(y=>y.BookId ).ToList())
.ToList();
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2.3 多對多
//多對多
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:簡單用法
var list3= db.Queryable<A1>().Includes(x => x.BList).ToList();
//例2:支援子物件排序和過濾
var list3= db.Queryable<A1>().Includes(x => x.BList.Where(z=>z.Id>0).ToList()).ToList();
//例3:支援主表過濾 Any和Count
var list3= db.Queryable<A1>().Includes(x => x.BList)
.Where(x=>x.BList .Any(z=>z.Id ==1)).ToList();
2.4 多級查詢
配置好實體類，我們可以多級查詢 ，.NET 中輕鬆多級查詢
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var list=db.Queryable<Test>()
.Includes(x => x.Provinces,x=>x.Citys ,x=>x.Street)//有時候沒提示 直接寫
.Includes(x => x.ClassInfo)// 一級查詢
.ToList();
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2.5 大資料分頁導航
適合一次性查詢1000條以上的導航
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var list = new List<Tree1>();
db.Queryable<Tree1>()
.Includes(it => it.Child)
.ForEach(it => list.Add(it), 300); //每次查詢300條
|
更多用法：https://www.donet5.com/Home/Doc?typeId=2414
3、ORM無配置對映（高效能）
適合沒有主鍵或者複雜的一些操作
3.1 無配置對映實現二層
結構: Student->SchoolA
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var list = db.Queryable<StudentA>().ToList();
db.ThenMapper(list, stu =>
{
//如果加Where不能帶有stu引數，stu引數寫到 SetContext
stu.SchoolA=db.Queryable<SchoolA>().SetContext(scl=>scl.SchoolId,()=>stu.SchoolId,stu).FirstOrDefault();
});
// SetContext不會生成迴圈操作，高效能 和直接Where效能是不一樣的
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如果沒有SetContext那麼這個查詢將會迴圈
3.2 無配置對映無限級
瞭解原理後我們用ThenMapper想對映哪層就對映哪層
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var treeRoot=db.Queryable<Tree>().Where(it => it.Id == 1).ToList();
//第一層
db.ThenMapper(treeRoot, item =>
{
item.Child = db.Queryable<Tree>().SetContext(x => x.ParentId, () => item.Id, item).ToList();
});
//第二層
db.ThenMapper(treeRoot.SelectMany(it=>it.Child), it =>
{
it.Child = db.Queryable<Tree>().SetContext(x => x.ParentId, () => it.Id, it).ToList();
});
//第三層
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();
});
//這兒只是用樹型結構來證明可以實現無限級別導航查詢 ,實際開發中樹型結構用ToTree實現
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不會生成迴圈操作，高效能 和直接Where效能是不一樣的
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4 、.NET ORM 未來計劃
Json to sql 正在開發中 ，未來將打造一套直接由前端操作資料庫的API
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{
"Queryable":"order",
Select:[ [{SqlFunc_AggregateMin:["id"]},"id"], [{SqlFunc_GetDate:[]},"Date"] ]
}
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將支援 許可權過濾 ，驗證，多表查詢，層級導航查詢 等
GitHUB 原始碼：
https://github.com/donet5/SqlSugar
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轉 https://www.cnblogs.com/sunkaixuan/p/16142861.html