NQL.Net 简介

NQL.NET 是我最近在NDO(DOTNET DataAccess Object)的基础上并吸收了Hibernate,Rails框架中的活动记录,Castle中的活动记录,Grove,ActionPack,OQL的精华思想上建立的一套数据库对象查询语言（NQL，NDO Query Language）它支持 CRUD操作，也包括 select、from、join、on、where、group by、having、order by 和 case 子句。

本文中的代码都以SQL SERVER 2000中的数据库Northwind 做为例子,代码以CSharp为例,其中的例子都是我做过严格的测试.

数据库配置

导入NQL包 : using NDO;

1.Filter 过滤器

this.dataGrid1.DataSource = new Query("Products")

.Filter("UnitPrice*UnitsInStock >=1000")

.GetDataTable();

上面的程序生成的SQL 语句是

SELECT *

FROM Products

WHERE

UnitPrice*UnitsInStock >=1000

2.邦定参数的Filter 过滤器

this.dataGrid1.DataSource = new Query("Products")

.Filter("UnitPrice*UnitsInStock >=@AA")

.AddParam("AA",1000)

.GetDataTable();

SQL 输出

SELECT *

FROM Products

WHERE

UnitPrice*UnitsInStock >=@AA

3.Where 的简单用法(该例子中用到了泛性的活动记录)

this.dataGrid1.DataSource = new ActiveRecord("Orders")

.SelectCommand

.Where("ShipVia",2)

.Asc("CustomerID","OrderID")

.GetDataTable();

SQL 输出

SELECT

[OrderID],

[CustomerID],

[EmployeeID],

[OrderDate],

[RequiredDate],

[ShippedDate],

[ShipVia],

[Freight],

[ShipName],

[ShipAddress],

[ShipCity],

[ShipRegion],

[ShipPostalCode],

[ShipCountry]

FROM

[Orders]

WHERE

([Orders].[ShipVia] = @ShipVia)

ORDER BY CustomerID,OrderID ASC

4.子查询的运用

Query qryCustomer = new Query("Customers")

.SelectColumn("CustomerID")

.Where("ContactTitle","Owner");

this.dataGrid1.DataSource = new Query("Orders")

.NewWhere("ShipVia",1)

.And(Ex.In("CustomerID",qryCustomer)).GetDataTable();

SQL 输出

SELECT *

FROM Orders

WHERE

[Orders].[ShipVia] = @ShipVia

AND [Orders].[CustomerID] IN (

SELECT

[Customers].[CustomerID]

FROM Customers

WHERE

([Customers].[ContactTitle] = @ContactTitle)

)

5.模糊查询

this.dataGrid1.DataSource = new Query("Customers")

.NewWhere(Ex.Like("ContactTitle","Sales%"))

.GetDataTable();

SQL 输出

SELECT *

FROM Customers

WHERE

[Customers].[ContactTitle] LIKE @ContactTitle

6.投影和多表连接操作

Query q = new Query("Orders","a");

this.dataGrid1.DataSource = q

.SelectColumn("OrderID")

._("OrderDate")

._("RequiredDate")

._("b","ProductID")

.InnerJoin("Order Details").As ("b")

.On(q.NewCondition("OrderID") == q.NewCondition("b","OrderID"))

.NewWhere("EmployeeID",5)

.And("ShipVia",1)

.GetDataTable();

SQL 输出

SELECT

[a].[OrderID],

[a].[OrderDate],

[a].[RequiredDate],

[b].[ProductID]

FROM Orders a

INNER JOIN [Order Details] b

ON [a].[OrderID]=b.[OrderID]

WHERE

[a].[EmployeeID] = @a_EmployeeID

AND [a].[ShipVia] = @a_ShipVia

7.简单的插入查询

new SimpleInsertQuery("Region").Values(this.textBox1.Text,this.textBox2.Text).Execute();
this.dataGrid1.DataSource = new Query("Region").GetDataTable();

SQL 输出

INSERT INTO [Region] VALUES (

@RegionID,@RegionDescription

)

SELECT *

FROM Region

8.插入语句2

new SimpleInsertQuery("Region").Columns("RegionID","RegionDescription").Values(this.textBox1.Text,this.textBox2.Text).Execute();
this.dataGrid1.DataSource = new Query("Region").GetDataTable();

SQL 输出

INSERT INTO [Region] (

RegionID,RegionDescription

) VALUES (

@RegionID,@RegionDescription

)

SELECT *

FROM Region

9.删除

new SimpleDeleteQuery("Region").Where("RegionID",this.textBox1.Text).Execute();

this.dataGrid1.DataSource = new Query("Region").Asc("RegionID").GetDataTable();

SQL 输出

DELETE FROM [Region]

WHERE

[Region].[RegionID] = @RegionID

SELECT *

FROM Region

ORDER BY RegionID ASC

10.删除2

new SimpleDeleteQuery("Region")

.Filter("RegionID=@RegionID")

.AddParam("RegionID",this.textBox1.Text)

.Execute();

this.dataGrid1.DataSource = new Query("Region").Asc("RegionID").GetDataTable();

SQL 输出同上

11.删除3,默认按照数据中的主键进行删除

new SimpleDeleteQuery("Region")

.Execute(this.textBox1.Text);

this.dataGrid1.DataSource = new Query("Region").Asc("RegionID").GetDataTable();

SQL 输出同上

12. 更新操作

new SimpleUpdateQuery("Region")

.Set("RegionDescription",this.textBox2.Text)

.Where("RegionID",this.textBox1.Text)

.Execute();

SQL 输出

UPDATE [Region] SET

[Region].[RegionDescription]=@RegionDescription

WHERE

[Region].[RegionID] = @RegionID

SELECT *

FROM Region

ORDER BY RegionID ASC

13.计算列的加法运算(可以对计算列进行斯则混合运算)

Query q = new Query("Region");

this.dataGrid1.DataSource = q

._(q["RegionID"] + 10)

._("RegionDescription")

.Asc("RegionID")

.GetDataTable();

SQL 输出

SELECT

[Region].[RegionID] + 10 AS [RegionID],

[Region].[RegionDescription]

FROM Region

ORDER BY RegionID ASC

14.计算列的乘法运算

Query q = new Query("Region");

this.dataGrid1.DataSource = q

._(q["RegionID"] * 2 + 5)

._("RegionDescription")

.Asc("RegionID").GetDataTable();

SQL 输出

SELECT

[Region].[RegionID] * 2 + 5 AS [RegionID],

[Region].[RegionDescription]

FROM Region

ORDER BY RegionID ASC

15.计算列的括弧运算

Query q = new Query("Region");

this.dataGrid1.DataSource = q

._((q["RegionID"] + 5)*2)

._("RegionDescription")

.Asc("RegionID").GetDataTable();

SQL 输出

SELECT

([Region].[RegionID] + 5) * 2 AS [RegionID],

[Region].[RegionDescription]

FROM Region

ORDER BY RegionID ASC

16.计算列的自增运算(自减运算同自增略)

Query q = new Query("Region");

QueryColumn col = q["RegionID"];

col = col ++;

this.dataGrid1.DataSource = q

._(col)

._("RegionDescription")

.Asc("RegionID").GetDataTable();

SQL 输出

SELECT

[Region].[RegionID] + 1 AS [RegionID],

[Region].[RegionDescription]

FROM Region

ORDER BY RegionID ASC

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