轻量ORM-SqlRepoEx （十四）最佳实践之Dapper

Posted 2021-01-14 a.thinker

简介：SqlRepoEx是 .Net平台下兼容.NET Standard 2.0人一个轻型的ORM。解决了Lambda转Sql语句这一难题，SqlRepoEx使用的是Lambda表达式，所以，对c#程序员来说，是非常简单的，其语法特点与Linq to Sql极为相似。不仅实现了完整的Select、Insert、Update、Delete等语句解析器，同时，也实现了Select、where、order by等子句，这些语句与子句均支持导出SQL语句，使得拼接复杂场景SQL语句变得轻松，SqlRepoEx很快其原生数据访问与Dapper不相上下，SqlRepoEx本身支持Sql Server与mysql方言，同时通过SqlRepoEx.Normal支持非方言SQL。SqlRepoEx没侵入性，仅通过简单的几个特性，就能让类与数据库关联起来；

*本系列以静态工厂为例；

*数据来源于Northwind数据库；

*完整的代码见   SqlRepoEx2.2.1 GitHub示例  SqlRepoEx2.2.1 码云示例

一、IDbConnection

可通过下列两种方式获取

1、工厂获取

private static IDbConnection dbConnection = MsSqlRepoFactory.DbConnection;

 

2、数据仓储

var repository = MsSqlRepoFactory.Create<AzProducts>();

IDbConnection dbConnection = repository.DbConnection;

 

二、 SQL语句中 @ 参数的生成和定义

 

1、SqlRepoEx的Insert、Updata 增加了ParamSql()方法获取  @ 参数 语句；

 

2、对于Where条件语句中，如要生成  @ 参数 语句 只需要在表达式中 .Where(p => p.ProductID == p.ProductID);右侧表达式中使用类型属性表达式即可。

 

3、关于数据字段与属性联，将在下篇中介绍

 

三、 简单查询

 

public static void QueryOnly()

{

 // 创建数据仓储

var repository = MsSqlRepoFactory.Create<AzProducts>();

        //查询

var result = repository.Query().Top(10);

Console.WriteLine(result.Sql());

// 通过 Dapper 获取数据

IEnumerable<AzProducts> azProducts = dbConnection.Query<AzProducts>(result.Sql());

// 显示结果（只取两列，仅为显示目的）

foreach (var item in azProducts)

{

Console.WriteLine($"{item.ProductID} {item.ProductName2}");

}

      }

此方法生成的 SQL

SELECT TOP (10) [dbo].[Products].[ProductID]

, [dbo].[Products].[ProductName] as [ProductName2]

, [dbo].[Products].[SupplierID]

, [dbo].[Products].[CategoryID]

, [dbo].[Products].[QuantityPerUnit]

, [dbo].[Products].[UnitPrice]

, [dbo].[Products].[UnitsInStock]

, [dbo].[Products].[UnitsOnOrder]

, [dbo].[Products].[ReorderLevel]

, [dbo].[Products].[Discontinued]

FROM [dbo].[Products];

此方法生成的结果

1       Chai

2       Chang

3       Aniseed Syrup

4       Chef Anton‘s Cajun Seasoning

5       Chef Anton‘s Gumbo Mix

6       Grandma‘s Boysenberry Spread

7       Uncle Bob‘s Organic Dried Pears

8       Northwoods Cranberry Sauce

9       Mishi Kobe Niku

10      Ikura

 

四、InnerJoin 查询

* LeftOuterJoin、RightOuterJoin与此例相似

        public static void DoInnerJoin()

        {

 // 创建数据仓储

var repository = MsSqlRepoFactory.Create<AzProducts>();

// 构建查询语句，相较而言，语法更接近于SQL，与Linq是有很大区别的

var result = repository.Query()

   .InnerJoin<AzSuppliers>()

   .On<AzSuppliers>((l, r) => l.SupplierID == r.SupplierID, r => r.CompanyName)

   .Top(10);

Console.WriteLine(result.Sql());

Console.WriteLine();

// 通过 Dapper 获取数据

IEnumerable<AzProducts> azProducts = dbConnection.Query<AzProducts>(result.Sql());

foreach (var item in azProducts)

{

Console.WriteLine($"{item.ProductID} {item.ProductName2} {item.Supplier}");

}

        }

此方法生成的 SQL

SELECT TOP (10) [dbo].[Products].[ProductID]

, [dbo].[Products].[ProductName] as [ProductName2]

, [dbo].[Products].[SupplierID]

, [dbo].[Products].[CategoryID]

, [dbo].[Products].[QuantityPerUnit]

, [dbo].[Products].[UnitPrice]

, [dbo].[Products].[UnitsInStock]

, [dbo].[Products].[UnitsOnOrder]

, [dbo].[Products].[ReorderLevel]

, [dbo].[Products].[Discontinued]

, [dbo].[Suppliers].[CompanyName] as [Supplier]

FROM [dbo].[Products]

INNER JOIN [dbo].[Suppliers]

ON [dbo].[Products].[SupplierID] = [dbo].[Suppliers].[SupplierID];

此方法生成的结果

1       Chai    Exotic Liquids

2       Chang   Exotic Liquids

3       Aniseed Syrup   Exotic Liquids

4       Chef Anton‘s Cajun Seasoning    New Orleans Cajun Delights

5       Chef Anton‘s Gumbo Mix  New Orleans Cajun Delights

6       Grandma‘s Boysenberry Spread    Grandma Kelly‘s Homestead

7       Uncle Bob‘s Organic Dried Pears Grandma Kelly‘s Homestead

8       Northwoods Cranberry Sauce      Grandma Kelly‘s Homestead

9       Mishi Kobe Niku Tokyo Traders

10      Ikura   Tokyo Traders

 

五、条件查询

 

        public static void QueryWhere()

        {

 // 创建数据仓储

            var repository = MsSqlRepoFactory.Create<AzProducts>();

            var result = repository.Query()

                                    .Where(p => p.ProductName2.Contains("t") && p.ProductID < 100)

                                    .Top(10);

            Console.WriteLine(result.Sql());

            Console.WriteLine();

 // 通过 Dapper 获取数据

            IEnumerable<AzProducts> azProducts = dbConnection.Query<AzProducts>(result.Sql());

 

            foreach (var item in azProducts)

            {

                Console.WriteLine($"{item.ProductID} {item.ProductName2}");

            }

        }

此方法生成的 SQL

SELECT TOP (10) [dbo].[Products].[ProductID]

, [dbo].[Products].[ProductName] as [ProductName2]

, [dbo].[Products].[SupplierID]

, [dbo].[Products].[CategoryID]

, [dbo].[Products].[QuantityPerUnit]

, [dbo].[Products].[UnitPrice]

, [dbo].[Products].[UnitsInStock]

, [dbo].[Products].[UnitsOnOrder]

, [dbo].[Products].[ReorderLevel]

, [dbo].[Products].[Discontinued]

FROM [dbo].[Products]

WHERE ((([dbo].[Products].[ProductName] LIKE ‘%t%‘) and ([dbo].[Products].[ProductID] < 100)));

此方法生成的结果

4       Chef Anton‘s Cajun Seasoning

5       Chef Anton‘s Gumbo Mix

8       Northwoods Cranberry Sauce

12      Queso Manchego La Pastora

14      Tofu

17      Alice Mutton

18      Carnarvon Tigers

19      Teatime Chocolate Biscuits

22      Gustaf‘s Kn?ckebr?d

23      Tunnbr?d

 

 

六、Union

      public static void QueryUnion()

        {

// 创建数据仓储

            var repository = MsSqlRepoFactory.Create<AzCustomers>();

            // 此语句不会参与数据查询，只是作为Union的包裹

            // 如果此语句本身也是数据查询，请增加到new List<UnionSql>中

            var result = repository.Query()

                                   .Select(c => c.CustomerID, c => c.CompanyName);

            var result01 = repository.Query()

                                    .Select(c => c.CustomerID, c => c.CompanyName)

                                    .Where(c => c.CustomerID == "ANATR");

            var result02 = repository.Query()

                                    .Select(c => c.CustomerID, c => c.CompanyName)

                                    .Where(c => c.CustomerID == "FRANK");

            var result03 = repository.Query()

                                    .Select(c => c.CustomerID, c => c.CompanyName)

                                    .Where(c => c.CustomerID == "TRADH");

            var resultAllSql = result.UnionSql(new List<UnionSql>  {

                UnionSql.New(  result01,UnionType.Union ),

                UnionSql.New(  result02,UnionType.Union ),

                UnionSql.New(  result03,UnionType.Union ), });

            Console.WriteLine(resultAllSql);

            Console.WriteLine();

// 通过 Dapper 获取数据

            IEnumerable<AzCustomers> azCustomers = dbConnection.Query<AzCustomers>(resultAllSql);

            foreach (var item in azCustomers)

            {

                Console.WriteLine($"{item.CustomerID} {item.CompanyName}");

            }

        }

此方法生成的 SQL

SELECT [_this_is_union].[CustomerID]

, [_this_is_union].[CompanyName]

FROM ( SELECT [dbo].[Customers].[CustomerID]

, [dbo].[Customers].[CompanyName]

FROM [dbo].[Customers]

WHERE (([dbo].[Customers].[CustomerID] = ‘ANATR‘))

UNION

 SELECT [dbo].[Customers].[CustomerID]

, [dbo].[Customers].[CompanyName]

FROM [dbo].[Customers]

WHERE (([dbo].[Customers].[CustomerID] = ‘FRANK‘))

UNION

 SELECT [dbo].[Customers].[CustomerID]

, [dbo].[Customers].[CompanyName]

FROM [dbo].[Customers]

WHERE (([dbo].[Customers].[CustomerID] = ‘TRADH‘)) )

AS  _this_is_union

此方法生成的结果

ANATR   Ana Trujillo Emparedados y helados

FRANK   Frankenversand

TRADH   Tradi??o Hipermercados

 

七、增加（使用实例）

public static void DoInsertEntityParam()

        {

            var repository = MsSqlRepoFactory.Create<AzProducts>();

            AzProducts azProduct = new AzProducts { ProductName2 = "testvalue" };

            var resultinsert = repository

                                    .Insert();

           // 使用ParamSql()方法获取 @ 参数SQL语句

            Console.WriteLine(resultinsert.ParamSql());

            Console.WriteLine();

 

            // 需返回自增字段，所以用Query

            IEnumerable<AzProducts> azProducts = dbConnection.Query<AzProducts>(resultinsert.ParamSql(), azProduct);

 

            foreach (var item in azProducts)

            {

                Console.WriteLine($"{item.ProductID} {item.ProductName2}");

            }

 

        }

此方法生成的 SQL

INSERT [dbo].[Products]([ProductName],[SupplierID],[CategoryID],[QuantityPerUnit],[UnitPrice],[UnitsInStock],[UnitsOnOrder],[ReorderLevel],[Discontinued])

VALUES(@ProductName2,@SupplierID,@CategoryID,@QuantityPerUnit,@UnitPrice,@UnitsInStock,@UnitsOnOrder,@ReorderLevel,@Discontinued);

SELECT [ProductID],[ProductName] as ProductName2,[SupplierID],[CategoryID],[QuantityPerUnit],[UnitPrice],[UnitsInStock],[UnitsOnOrder],[ReorderLevel],[Discontinued]

FROM [dbo].[Products]

WHERE [ProductID] = SCOPE_IDENTITY();

此方法生成的结果

96      testvalue

八、批增加（使用选择）

public static void DoInsertEntityParamBatch()

        {

            // 创建数据仓储

            var repository = MsSqlRepoFactory.Create<AzProducts>();

            // 设置要批处理的数据

            List<AzProducts> azProductList = new List<AzProducts>{

              new AzProducts { ProductName2 = "testvalue1" ,CategoryID=1,UnitPrice=123},

              new AzProducts { ProductName2 = "testvalue2" ,CategoryID=1,UnitPrice=123},

              new AzProducts { ProductName2 = "testvalue3" ,CategoryID=1,UnitPrice=123},

              new AzProducts { ProductName2 = "testvalue4" ,CategoryID=1,UnitPrice=123 },

              new AzProducts { ProductName2 = "testvalue5" ,CategoryID=1,UnitPrice=123},

              new AzProducts { ProductName2 = "testvalue6" ,CategoryID=1,UnitPrice=123},

            };

           // 使用选择增加

            var resultinsert = repository

                                    .Insert().ParamWith(c => c.ProductName2, c => c.UnitPrice, c => c.CategoryID);

 

            Console.WriteLine(resultinsert.ParamSql());

            Console.WriteLine();

 

            // 通过 Dapper 批处理

            dbConnection.Execute(resultinsert.ParamSql(), azProductList);

       }

此方法生成的 SQL

INSERT [dbo].[Products]([ProductName],[UnitPrice],[CategoryID])

VALUES(@ProductName2,@UnitPrice,@CategoryID);

SELECT [ProductName] as ProductName2,[UnitPrice],[CategoryID],[ProductID]

FROM [dbo].[Products]

WHERE [ProductID] = SCOPE_IDENTITY();

 

九、更新

        public static void DoUpdateEntityParam()

        {

           // 创建数据仓储

            var repository = MsSqlRepoFactory.Create<AzProducts>();

           // 构建更新语句

            var resultUpdate = repository

                                    .Update()

                                    .ParamSet(p => p.ProductName2, p => p.CategoryID)

           // Where 中使用下列格式语句，可生成带 @ 的参数

                                    .Where(p => p.ProductID == p.ProductID);

            Console.WriteLine(resultUpdate.ParamSql());

            Console.WriteLine();

           // 需更新的数据

            AzProducts products = new AzProducts() { ProductID = 84, ProductName2 = "testvalue100", CategoryID = 7 };

           // 通过 Dapper 更新数据

            int result = dbConnection.Execute(resultUpdate.ParamSql(), products);

           Console.WriteLine($"{result}");

        }

此方法生成的 SQL

UPDATE [dbo].[Products]

SET ProductName  = @ProductName2, CategoryID  = @CategoryID

WHERE (([dbo].[Products].[ProductID] = @ProductID));

 

十、删除

        public static void DoDeleteEntity(bool go = false)

        {

 // 创建数据仓储

            var repository = MsSqlRepoFactory.Create<AzProducts>();

           // 要删除的数据

            AzProducts azProducts = new AzProducts { ProductName2 = "testvalue", ProductID = 81 };

            // 构建删除，使用实例构建时，如果不设置 Where 语句

           // SqlRepoEx 会以关键词来构建  Where 语句

            var resultUpdate = repository.Delete().For(azProducts);

            Console.WriteLine(resultUpdate.Sql());

            Console.WriteLine();

           // 通过 Dapper 删除数据

            int result = dbConnection.Execute(resultUpdate.Sql());

            Console.WriteLine($"{result}");

        }

此方法生成的 SQL

DELETE [dbo].[Products]

WHERE (([dbo].[Products].[ProductID] = @ProductID));

 

十一、使用事务

public static void DoDeleteTransaction()

        {

           // 创建数据仓储

            var repository = MsSqlRepoFactory.Create<AzProducts>();

           // 构建删除，如果不是实例构建，用户必需自行指定删除条件

            // Where 中使用下列格式语句，可生成带 @ 的参数

            var resultUpdate = repository.Delete().Where(p => p.ProductID == p.ProductID);

               // 要删除的数据集

            List<AzProducts> azProductList = new List<AzProducts>

            {

                new AzProducts{ProductID=92},

                new AzProducts{ProductID=93},

                new AzProducts{ProductID=94},

                new AzProducts{ProductID=91},

            };

            Console.WriteLine(resultUpdate.Sql());

            Console.WriteLine();

            // 使用事务控制

            using (var transaction = dbConnection.BeginTransaction())

            {

           //  通过 Dapper 删除，同时指定了事务

                dbConnection.Execute(resultUpdate.Sql(), azProductList, transaction: transaction);

           // 仅为了演示，此处回滚事务，取消删除

           // 如果相要提交事务，请将此处改为 transaction.Commit() 可看到删除效果

                transaction.Rollback();

            }

        }

此方法生成的 SQL

DELETE [dbo].[Products]

WHERE (([dbo].[Products].[ProductID] = @ProductID));