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($"{item.ProductID}\t{item.ProductName2}");
}
}
此方法生成的 SQL
SELECT TOP (10) [dbo].[Products].[ProductID]
, [dbo].[Products].[ProductName] as [ProductName2]
, [dbo].[Products].[SupplierID]
, [dbo].[Products].[CategoryID]
, [dbo].[Products].[QuantityPerUnit]
, [dbo].[Products].[UnitPrice]
, [dbo].[Products].[UnitsInStock]
, [dbo].[Products].[UnitsOnOrder]
, [dbo].[Products].[ReorderLevel]
, [dbo].[Products].[Discontinued]
FROM [dbo].[Products];
此方法生成的结果
1 Chai
2 Chang
3 Aniseed Syrup
4 Chef Anton's Cajun Seasoning
5 Chef Anton's Gumbo Mix
6 Grandma's Boysenberry Spread
7 Uncle Bob's Organic Dried Pears
8 Northwoods Cranberry Sauce
9 Mishi Kobe Niku
10 Ikura
四、InnerJoin 查询
* LeftOuterJoin、RightOuterJoin与此例相似
public static void DoInnerJoin()
{
// 创建数据仓储
var repository = MsSqlRepoFactory.Create<AzProducts>();
// 构建查询语句，相较而言，语法更接近于SQL，与Linq是有很大区别的
var result = repository.Query()
.InnerJoin<AzSuppliers>()
.On<AzSuppliers>((l, r) => l.SupplierID == r.SupplierID, r => r.CompanyName)
.Top(10);
Console.WriteLine(result.Sql());
Console.WriteLine();
// 通过 Dapper 获取数据
IEnumerable<AzProducts> azProducts = dbConnection.Query<AzProducts>(result.Sql());
foreach (var item in azProducts)
{
Console.WriteLine($"{item.ProductID}\t{item.ProductName2}\t{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($"{item.ProductID}\t{item.ProductName2}");
}
}
此方法生成的 SQL
SELECT TOP (10) [dbo].[Products].[ProductID]
, [dbo].[Products].[ProductName] as [ProductName2]
, [dbo].[Products].[SupplierID]
, [dbo].[Products].[CategoryID]
, [dbo].[Products].[QuantityPerUnit]
, [dbo].[Products].[UnitPrice]
, [dbo].[Products].[UnitsInStock]
, [dbo].[Products].[UnitsOnOrder]
, [dbo].[Products].[ReorderLevel]
, [dbo].[Products].[Discontinued]
FROM [dbo].[Products]
WHERE ((([dbo].[Products].[ProductName] LIKE '%t%') and ([dbo].[Products].[ProductID] < 100)));
此方法生成的结果
4 Chef Anton's Cajun Seasoning
5 Chef Anton's Gumbo Mix
8 Northwoods Cranberry Sauce
12 Queso Manchego La Pastora
14 Tofu
17 Alice Mutton
18 Carnarvon Tigers
19 Teatime Chocolate Biscuits
22 Gustaf's Kn?ckebr?d
23 Tunnbr?d
六、Union
public static void QueryUnion()
{
// 创建数据仓储
var repository = MsSqlRepoFactory.Create<AzCustomers>();
// 此语句不会参与数据查询，只是作为Union的包裹
// 如果此语句本身也是数据查询，请增加到new List<UnionSql>中
var result = repository.Query()
.Select(c => c.CustomerID, c => c.CompanyName);
var result01 = repository.Query()
.Select(c => c.CustomerID, c => c.CompanyName)
.Where(c => c.CustomerID == "ANATR");
var result02 = repository.Query()
.Select(c => c.CustomerID, c => c.CompanyName)
.Where(c => c.CustomerID == "FRANK");
var result03 = repository.Query()
.Select(c => c.CustomerID, c => c.CompanyName)
.Where(c => c.CustomerID == "TRADH");
var resultAllSql = result.UnionSql(new List<UnionSql> {
UnionSql.New( result01,UnionType.Union ),
UnionSql.New( result02,UnionType.Union ),
UnionSql.New( result03,UnionType.Union ), });
Console.WriteLine(resultAllSql);
Console.WriteLine();
// 通过 Dapper 获取数据
IEnumerable<AzCustomers> azCustomers = dbConnection.Query<AzCustomers>(resultAllSql);
foreach (var item in azCustomers)
{
Console.WriteLine($"{item.CustomerID}\t{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}\t{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));
