连表查询实现（统计“一班”的学生个数）

2015-04-06 08:52:49 访问(1217) 赞(0) 踩(0)

生成和输出的SQL语句

select count(1) from UTB_EXAM_STUDENT t , 
UTB_EXAM_CLASS tClass where t.ClassId = tClass.ID and tClass.TheName = '一班' 

@tClassp2 = '一班'


select count(1) from UTB_EXAM_STUDENT t , 
UTB_EXAM_CLASS tClass where t.ClassId = tClass.ID and tClass.TheName = @tClassp2 

@tClassp2 	 一班 	 String 	 Input 	 SqlParameter

关键代码

IFromTableDriver ifrom = entity;
            ifrom.AddIFromTableItemWithBaseEntity("tClass", entityClass);

            IQueryDriver iq = entity;
            iq.AddIQueryItemWithEntityFieldInfo(entity._ClassId, entityClass._ID);
            iq.AddIQueryItemWithEntityFieldInfo(entityClass._TheName, "一班");

            ISelectDriver iselect = entity;
            iselect.AddISelectItemWithEntityFieldInfo
                (
                    entity._ID
                );

            string theCount = bll.Count(entity, xdbHelper).ToString();

代码写法

using System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using SlowX.DAL.Helpers;
using SlowX.Core.ICoreClasses;
using System.Data;
using SlowX.Functions.Functions;
using SlowX.Core.CoreClasses;

public partial class ExamSQL : System.Web.UI.Page
{
    protected string strResult = "";

    protected void Page_Load(object sender, EventArgs e)
    {
        DataBindTheContorls(null);
    }

    #region 操作

    /// <summary>
    /// 
    /// </summary>
    /// <param name="xdbHelper"></param>
    protected void DataBindTheContorls(DBHelper xdbHelper)
    {
        string theResult = null;
        bool bIsCreate = true;

        if (xdbHelper == null)
        {
            xdbHelper = SlowX.DAL.Helpers.DBHelper.CreateDBHelper();
        }
        else
        {
            // 没有打开链接 //
            bIsCreate = xdbHelper.IsNotOpen();
        }

        try
        {
            if (bIsCreate)
                xdbHelper.OpenDBHelper();

            SlowX.ExamLib.Business.UTB_EXAM_STUDENT
             bll
             =
             SlowX.ExamLib.Business.UTB_EXAM_STUDENT.instance;

            SlowX.ExamLib.Entity.UTB_EXAM_STUDENT
                entity
                =
                new SlowX.ExamLib.Entity.UTB_EXAM_STUDENT();

            SlowX.ExamLib.Entity.UTB_EXAM_CLASS
                entityClass
                =
                new SlowX.ExamLib.Entity.UTB_EXAM_CLASS();

            IFromTableDriver ifrom = entity;
            ifrom.AddIFromTableItemWithBaseEntity("tClass", entityClass);

            IQueryDriver iq = entity;
            iq.AddIQueryItemWithEntityFieldInfo(entity._ClassId, entityClass._ID);
            iq.AddIQueryItemWithEntityFieldInfo(entityClass._TheName, "一班");

            ISelectDriver iselect = entity;
            iselect.AddISelectItemWithEntityFieldInfo
                (
                    entity._ID
                );

            string theCount = bll.Count(entity, xdbHelper).ToString();  
  

            theResult =
                @"<textarea name=""TextBox1"" rows=""2"" cols=""20"" id=""TextBox1"" style=""height:400px;width:99%;"">"
                + bll.BuildSqlCount( entity, xdbHelper)
                + "</textarea>";

            theResult += "<br /><br />";

            theResult += theCount;

            

            if (bIsCreate)
                xdbHelper.EndDBHelper();

        }
        catch (Exception err)
        {
            if (bIsCreate)
                xdbHelper.TranDBHelper();

            throw err;
        }
        finally
        {
            if (bIsCreate)
                xdbHelper.FinallyDBHelper();
        }

        strResult = theResult;
    }

    #endregion 操作

}