轻量ORM-SqlRepoEx JOIN
Posted a.thinker
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示例使用的是最新 SqlRepoEx 2.0.2
可在:https://github.com/AzThinker/SqlRepoEx2.0Demo
或:https://gitee.com/azthinker/SqlRepoEx2.0Demo
演示模块:GettingStartedNorthwind
1、新建一个控制台程序;
2、通过Nuget包管理,下载SqlRepoEx.MsSql.Static
3、根据Northwind数据库的 Orders、Customers、Employees三张表结构生成三个简单的同名类;
4、 创建初始方法,初始一个工厂类。
1 /// <summary> 2 /// init 3 /// 创建初始方法,初始一个工厂类。 4 /// </summary> 5 static void Init() 6 { 7 // Set Connection String 8 string ConnectionString = "Data Source=(Local);Initial Catalog=Northwind;User ID=test;Password=test"; 9 var connectionProvider = new ConnectionStringConnectionProvider(ConnectionString); 10 MsSqlRepoFactory.UseConnectionProvider(connectionProvider); 11 12 // this Demo is POJO ,So Using SimpleWritablePropertyMatcher()。 13 // 本例中,使用的是简单类,所以用SimpleWritablePropertyMatcher()来操作属性。 14 MsSqlRepoFactory.UseWritablePropertyMatcher(new SimpleWritablePropertyMatcher()); 15 }
5、为了演示JOIN 在 Orders类增加几个相关字段
(1)、关联Customers
public string CompanyName { get; set; }
(2)、 关联Employees
public string LastName { get; set; }
public string FirstName { get; set; }
6、实例一个Orders仓储
var repoCustomers = MsSqlRepoFactory.Create<Orders>();
7、使用 SqlRepoEx 建立一个联接查询
1 var cust = repoCustomers.Query().Select(c => c.OrderID, c => c.CompanyName, c => c.FirstName, c => c.LastName, c => c.OrderDate) 2 .InnerJoin<Customers>() 3 .On<Customers>((r, l) => r.CustomerID == l.CustomerID, l => l.CompanyName) 4 .InnerJoin<Employees>() 5 .On<Employees>((k, q) => k.EmployeeID == q.EmployeeID, q => q.FirstName, q => q.LastName) 6 .Top(10);
8、此查询的实际 SQL 语句
Console.WriteLine(cust.Sql());
...
1 SELECT TOP (10) [dbo].[Orders].[OrderID] 2 , [dbo].[Customers].[CompanyName] 3 , [dbo].[Employees].[FirstName] 4 , [dbo].[Employees].[LastName] 5 , [dbo].[Orders].[OrderDate] 6 FROM [dbo].[Orders] 7 INNER JOIN [dbo].[Customers] 8 ON [dbo].[Orders].[CustomerID] = [dbo].[Customers].[CustomerID] 9 INNER JOIN [dbo].[Employees] 10 ON [dbo].[Orders].[EmployeeID] = [dbo].[Employees].[EmployeeID];
9、查询结果
1 /// <summary> 2 /// Join 演示 3 /// </summary> 4 public static void DoJoin() 5 { 6 var repoCustomers = MsSqlRepoFactory.Create<Orders>(); 7 8 9 var cust = repoCustomers.Query().Select(c => c.OrderID, c => c.CompanyName, c => c.FirstName, c => c.LastName, c => c.OrderDate) 10 .InnerJoin<Customers>() 11 .On<Customers>((r, l) => r.CustomerID == l.CustomerID, l => l.CompanyName) 12 .InnerJoin<Employees>() 13 .On<Employees>((k, q) => k.EmployeeID == q.EmployeeID, q => q.FirstName, q => q.LastName) 14 .Top(10); 15 16 Console.WriteLine(cust.Sql()); 17 18 foreach(var item in cust.Go()) 19 { 20 Console.WriteLine($"{item.OrderID} {item.CompanyName} {item.FirstName} {item.LastName} {item.OrderDate};"); 21 } 22 23 }
1 10258 Ernst Handel Nancy Davolio 1996-07-17 0:00:00; 2 10270 Wartian Herkku Nancy Davolio 1996-08-01 0:00:00; 3 10275 Magazzini Alimentari Riuniti Nancy Davolio 1996-08-07 0:00:00; 4 10285 QUICK-Stop Nancy Davolio 1996-08-20 0:00:00; 5 10292 Tradi??o Hipermercados Nancy Davolio 1996-08-28 0:00:00; 6 10293 Tortuga Restaurante Nancy Davolio 1996-08-29 0:00:00; 7 10304 Tortuga Restaurante Nancy Davolio 1996-09-12 0:00:00; 8 10306 Romero y tomillo Nancy Davolio 1996-09-16 0:00:00; 9 10311 Du monde entier Nancy Davolio 1996-09-20 0:00:00; 10 10314 Rattlesnake Canyon Grocery Nancy Davolio 1996-09-25 0:00:00;
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