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 

< add  key ="ConnectionString"  value ="Data Source=localhost; Database=Northwind; Integrated Security=true;" />

 

  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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