使用PDF.NET数据开发框架的实体操作语言OQL构造复杂查询条件

PDF.NET数据开发框架（Pwmis Data develop Framework，http://www.pwmis.com/sqlmap) 是一套借鉴iBatis、Hibernate、Linq等数据访问框架而来的轻量级数据开发框架，主要特点是具有iBatis特点的SQL-MAP功能和框架独特的实体对象查询语言--OQL，下面我们使用OQL来构造一个复杂的实体查询。

 

首先定义两个实体类：用户类和订单类，可以使用框架提供的实体类生成器生成，下面是详细代码：

 

/*  
 本类由PWMIS 实体类生成工具(Ver 4.1)自动生成
  http://www.pwmis.com/sqlmap
 使用前请先在项目工程中引用 PWMIS.Core.dll
 2010/12/8 15:01:22
*/

using  System;
using  PWMIS.Common;
using  PWMIS.DataMap.Entity;

namespace  LocalDB 
{
     ///   <summary>
     ///  用户表
     ///   </summary>
  [Serializable()]
   public   partial   class  Table_User : EntityBase
  {
     public  Table_User()
    {
            TableName  =   " Table_User " ;
            EntityMap = EntityMapType.SqlMap;
             // IdentityName = "标识字段名";
    IdentityName = " UID " ;

             // PrimaryKeys.Add("主键字段名");
    PrimaryKeys.Add( " UID " );

            
            PropertyNames  =   new   string [] {  " UID " , " Name " , " Sex " , " Height " , " Birthday "  };
            PropertyValues  =   new   object [PropertyNames.Length]; 

    }


       ///   <summary>
       ///  用户标识
       ///   </summary>
       public  System.Int32 UID
      {
           get { return  getProperty < System.Int32 > ( " UID " );}
           set {setProperty( " UID " ,value );}
      }

       ///   <summary>
       ///  姓名
       ///   </summary>
       public  System.String Name
      {
           get { return  getProperty < System.String > ( " Name " );}
           set {setProperty( " Name " ,value , 50 );}
      }

       ///   <summary>
       ///  性别
       ///   </summary>
       public  System.Boolean Sex
      {
           get { return  getProperty < System.Boolean > ( " Sex " );}
           set {setProperty( " Sex " ,value );}
      }

       ///   <summary>
       ///  身高
       ///   </summary>
       public  System.Double Height
      {
           get { return  getProperty < System.Double > ( " Height " );}
           set {setProperty( " Height " ,value );}
      }

       ///   <summary>
       ///  出生日期
       ///   </summary>
       public  System.DateTime Birthday
      {
           get { return  getProperty < System.DateTime > ( " Birthday " );}
           set {setProperty( " Birthday " ,value );}
      }


  }

///   <summary>
///  订单表
///   </summary>
  [Serializable()]
   public   partial   class  Table_Order : EntityBase
  {
       public  Table_Order()
      {
          TableName  =   " Table_Order " ;
          EntityMap  =  EntityMapType.SqlMap;
           // IdentityName = "标识字段名";
          IdentityName  =   " OID " ;

           // PrimaryKeys.Add("主键字段名");
          PrimaryKeys.Add( " OID " );


          PropertyNames  =   new   string [] {  " OID " ,  " UID " ,  " ProductName " ,  " BuyCount " ,  " OrderDate "  };
          PropertyValues  =   new   object [PropertyNames.Length];

      }

       ///   <summary>
       ///  订单编号
       ///   </summary>
       public  System.Int32 OID
      {
           get  {  return  getProperty < System.Int32 > ( " OID " ); }
           set  { setProperty( " OID " , value); }
      }


       ///   <summary>
       ///  用户号
       ///   </summary>
       public  System.Int32 UID
      {
           get  {  return  getProperty < System.Int32 > ( " UID " ); }
           set  { setProperty( " UID " , value); }
      }

       ///   <summary>
       ///  产品名字
       ///   </summary>
       public  System.String Name
      {
           get  {  return  getProperty < System.String > ( " ProductName " ); }
           set  { setProperty( " ProductName " , value,  50 ); }
      }

       ///   <summary>
       ///  购买数量
       ///   </summary>
       public  System.Int32 Count
      {
           get  {  return  getProperty < System.Int32 > ( " BuyCount " ); }
           set  { setProperty( " BuyCount " , value); }
      }

      
       ///   <summary>
       ///  购买日期
       ///   </summary>
       public  System.DateTime OrderDate
      {
           get  {  return  getProperty < System.DateTime > ( " OrderDate " ); }
           set  { setProperty( " OrderDate " , value); }
      }


  }
}

 

然后，我们来构造两个复杂的查询条件，直接上代码：

 

using  System;
using  System.Collections.Generic;
using  System.Linq;
using  System.Text;
using  PWMIS.DataMap.Entity;

namespace  TestSqlMapEntity
{
     class  Program
    {
         static   void  Main( string [] args)
        {
            LocalDB.Table_User user  =   new  LocalDB.Table_User();
            List < OQLCompare >  OrCmp1  =   new  List < OQLCompare > ();
            OQLCompare cmp  =   new  OQLCompare(user);

            OrCmp1.Add(cmp.Comparer(user.UID,  " = " ,  1 ));
            OrCmp1.Add(cmp.Comparer(user.UID,  " = " ,  2 ));
            OrCmp1.Add(cmp.Comparer(user.UID,  " = " ,  3 ));

            List < OQLCompare >  OrCmp2  =   new  List < OQLCompare > ();
            OrCmp2.Add(cmp.Comparer(user.Name,  " = " ,  " aaa " ));
            OrCmp2.Add(cmp.Comparer(user.Name,  " = " ,  " bbb " ));

            OQLCompare result  =   new  OQLCompare(
                cmp.Comparer(OrCmp1, OQLCompare.CompareLogic.OR), 
                OQLCompare.CompareLogic.AND,
                cmp.Comparer(OrCmp2, OQLCompare.CompareLogic.OR));

            
            OQL oql  =  OQL.From(user).Select().Where(result).END;
            Console.WriteLine( " OQL To SQL is:\r\n "   +  oql.ToString());
             /*
             * 
             * OQL To SQL is:
SELECT UID,Name,Sex,Height,Birthday
 FROM Table_User
   Where  ( ( UID = @CP1 Or UID = @CP2 Or UID = @CP3 )  AND  ( Name = @CP4 Or Na
me = @CP5 ) )

              */
            oql.ReSet();

            LocalDB.Table_Order order  =   new  LocalDB.Table_Order();
            OQL q_order  =  OQL.From(order).Select(order.UID ).Where(
                 new  OQLCompare(order).Comparer(order.OrderDate,  " >= " , DateTime.Now.AddDays( - 10 ))
                ).END ;

            oql.Select().Where(oql.Condition.AND(user.Sex , " = " , true ).IN(user.UID, q_order));

            Console.WriteLine( " OQL To SQL is:\r\n "   +  oql.ToString());
             /*
             * 
OQL To SQL is:
SELECT UID,Name,Sex,Height,Birthday
 FROM Table_User
   Where  Sex = @Sex0 AND UID IN (
SELECT UID
 FROM Table_Order
   Where OrderDate >= @CP1
    )

              */

            Console.Read();
        }
}
}

 

程序中有两段代码，第一段代码是为了构造一个复杂的Where条件：

Where  ( ( UID = @CP1 Or UID = @CP2 Or UID = @CP3 )  AND  ( Name = @CP4 Or Name = @CP5 ) )

意思是查询符合条件的多个UID并且查询符合条件的多个用户姓名，输出的完整SQL语句如下：

 

SELECT  UID,Name,Sex,Height,Birthday
  FROM  Table_User
    Where   ( ( UID  =   @CP1   Or  UID  =   @CP2   Or  UID  =   @CP3  )   AND   ( Name  =   @CP4   Or  Name  =   @CP5  ) )

 

第二段代码是为了以UID为外键，从订单表中查询哪些用户在10日内提交了订单的用户信息，程序声明了两个OQL对象：

OQL oql;//用户相关的OQL对象；

OQL q_order //订单相关的OQL对象；

关键点在于q_order 对象作为oql对象的 IN 查询的参数，实现了SQL的IN子查询：

 

oql.Select().Where(oql.Condition.AND(user.Sex ,"=",true).IN(user.UID, q_order));

 

该条查询输出的完整SQL语句如下：

 

SELECT  UID,Name,Sex,Height,Birthday
  FROM  Table_User
    Where   Sex  =   @Sex0   AND  UID  IN  (
SELECT  UID
  FROM  Table_Order
    Where  OrderDate  >=   @CP1
    )

 

OK，到此为止，我们可以使用我们的OQL查询出真正的实体集合了：

 

List < LocalDB.Table_User >  result = EntityQuery < LocalDB.Table_User > .Query(oql);

 

一行代码搞定，是不是很简单？

 

PDF.NET的宗旨就是为了最大化精简你的数据开发，有兴趣请看我的博客其它文章或者到官网：http://www.pwmis.com/sqlmap