Question

我完成了我的学生日程安排课程，并且我的教授回复了我的工作，宣布＆＃34;日程安排是一个列表课程，而不仅仅是studentntid和crn＆＃34;

他的意思是什么？我该如何解决？

using System;
using System.Collections.Generic;
using System.Text;

namespace Schedule 
{
    class Schedule
    {
         private int studentID;
    private int cRN;



    public Schedule() {
        this.studentID = 0;
         this.cRN = 0;
    }

        //++++++++++++++++  DATABASE Data Elements +++++++++++++++++
        public System.Data.OleDb.OleDbDataAdapter OleDbDataAdapter;
        public System.Data.OleDb.OleDbCommand OleDbSelectCommand;
        public System.Data.OleDb.OleDbCommand OleDbInsertCommand;
        public System.Data.OleDb.OleDbCommand OleDbUpdateCommand;
        public System.Data.OleDb.OleDbCommand OleDbDeleteCommand;
        public System.Data.OleDb.OleDbConnection OleDbConnection;
        public string cmd;

        public void DBSetup(){
        // +++++++++++++++++++++++++++  DBSetup function +++++++++++++++++++++++++++
        // This DBSetup() method instantiates all the DB objects needed to access a DB, 
        // including OleDbDataAdapter, which contains 4 other objects(OlsDbSelectCommand, 
        // oleDbInsertCommand, oleDbUpdateCommand, oleDbDeleteCommand.) And each
        // Command object contains a Connection object and an SQL string object.
            OleDbDataAdapter = new System.Data.OleDb.OleDbDataAdapter();
            OleDbSelectCommand = new System.Data.OleDb.OleDbCommand();
            OleDbInsertCommand = new System.Data.OleDb.OleDbCommand();
            OleDbUpdateCommand = new System.Data.OleDb.OleDbCommand();
            OleDbDeleteCommand = new System.Data.OleDb.OleDbCommand();
            OleDbConnection = new System.Data.OleDb.OleDbConnection();


            OleDbDataAdapter.DeleteCommand = OleDbDeleteCommand;
            OleDbDataAdapter.InsertCommand = OleDbInsertCommand;
            OleDbDataAdapter.SelectCommand = OleDbSelectCommand;
            OleDbDataAdapter.UpdateCommand = OleDbUpdateCommand;


OleDbConnection.ConnectionString = "Jet OLEDB:Global Partial Bulk Ops=2;Jet OLEDB:Reg"+
"istry Path=;Jet OLEDB:Database L" + 
"ocking Mode=1;Data Source=C:\Users\Tina\Desktop\RegistrationMDB.accdb;J" + 
"et OLEDB:Engine Type=5;Provider=Microsoft.Jet.OLEDB.4.0;Jet OLEDB:System datab" + 
"ase=;Jet OLEDB:SFP=False;persist security info=False;Extended Properties=;Mode=S" + 
"hare Deny None;Jet OLEDB:Encrypt Database=False;Jet OLEDB:Create System Database=False;Jet " + 
"OLEDB:Don't Copy Locale on Compact=False;Jet OLEDB:Compact Without Replica Repai" + 
"r=False;User ID=Admin;Jet OLEDB:Global Bulk Transactions=1";

        }



        public void SelectDB(int studentID) 
        { //++++++++++++++++++++++++++  SELECT +++++++++++++++++++++++++
            DBSetup();
            cmd = "Select * from Courses where StudentID = " + studentID;
            OleDbDataAdapter.SelectCommand.CommandText = cmd;
            OleDbDataAdapter.SelectCommand.Connection = OleDbConnection;
            Console.WriteLine(cmd);
            try  {
                    OleDbConnection.Open();
                    System.Data.OleDb.OleDbDataReader dr;
                    dr = OleDbDataAdapter.SelectCommand.ExecuteReader();

                    dr.Read();


                setStudentID(Int32.Parse(dr.GetValue(1)+""));
                    setCRN(Int32.Parse(dr.GetValue(1)+""));

            }
            catch (Exception ex) 
            {
                Console.WriteLine(ex);
            }
            finally 
            {
                OleDbConnection.Close();
            }                    
        } 

        public void InsertDB() {
        // +++++++++++++++++++++++++++  INSERT +++++++++++++++++++++++++++++++

            DBSetup();
            cmd = "INSERT into StudentSchedule values(" + getStudentID() + "," +
                             "'" + getCRN() + ")";

            OleDbDataAdapter.InsertCommand.CommandText = cmd;
            OleDbDataAdapter.InsertCommand.Connection = OleDbConnection;
            Console.WriteLine(cmd);
            try  
            {
                OleDbConnection.Open();
                int n = OleDbDataAdapter.InsertCommand.ExecuteNonQuery();
                if (n==1)
                    Console.WriteLine("Data Inserted");
                else
                    Console.WriteLine("ERROR: Inserting Data");
            }
            catch (Exception ex) 
            {
                Console.WriteLine(ex);
            }
            finally 
            {
                OleDbConnection.Close();
            }                
        } 

        public void updateDB() 
        {
            //++++++++++++++++++++++++++  UPDATE  +++++++++++++++++++++++++

            cmd = "Update StudentSchedule set StudentID = '" + getStudentID() + "'," + 
                        "CRN = '" + getCRN();

            OleDbDataAdapter.UpdateCommand.CommandText = cmd;
            OleDbDataAdapter.UpdateCommand.Connection = OleDbConnection;
            Console.WriteLine(cmd);
            try  
            {
                OleDbConnection.Open();
                int n = OleDbDataAdapter.UpdateCommand.ExecuteNonQuery();
                if (n==1)
                    Console.WriteLine("Data Updated");
                else
                    Console.WriteLine("ERROR: Updating Data");
            }
            catch (Exception ex) 
            {
                Console.WriteLine(ex);
            }
            finally 
            {
                OleDbConnection.Close();
            }                    
        }
        public void deleteDB() 
        {   
            //++++++++++++++++++++++++++  DELETE  +++++++++++++++++++++++++

            cmd = "Delete from StudentSchedule where StudentID = " + getStudentID();
            OleDbDataAdapter.DeleteCommand.CommandText = cmd;
            OleDbDataAdapter.DeleteCommand.Connection = OleDbConnection;
            Console.WriteLine(cmd);
            try  
            {
                OleDbConnection.Open();
                int n = OleDbDataAdapter.DeleteCommand.ExecuteNonQuery();
                if (n==1)
                    Console.WriteLine("Data Deleted");
                else
                    Console.WriteLine("ERROR: Deleting Data");
            }
            catch (Exception ex) 
            {
                Console.WriteLine(ex);
            }
            finally 
            {
                OleDbConnection.Close();
            }                    
        }

       public void setStudentID(int studentID) {
        this.studentID = studentID;
    }
       public void setCRN(int cRN) {
        this.cRN = cRN;
    }
      public int getStudentID() {
        return studentID;
    } 
       public int getCRN() {
        return cRN;
    } 

         public void display(){
        System.Console.WriteLine("Student ID =  "+ getStudentID());
        System.Console.WriteLine("CRN =   "+ getCRN());



    }
    }
}

这是学生时间表

enter image description here
这是部分。

Answer 1

你应该问你的教授，但我会说你应该有一个Student课程，而Schedule会有一个List<Student>的属性。此外，您不应该/不应该将所有OleDb*公开。

Answer 2

您应该首先考虑日程安排 - 事件列表。如果您查看SelectDB，您只能存储一名学生和一门课程。但是如果你看一下你的select语句Select * from Courses WHERE StudentId = whatever，就有可能从查询中返回多行。

您应该拥有的是使用List<Courses>定义的日程安排类以及您需要的任何属性。

public class Schedule
{
    private int studentID;

    private List<Course> courseList;
}

您的课程对象可能类似于：

public class Course
{
    public int courseId;

    public int studentId;

    public int name;
}

这应该让你朝着正确的方向前进。

列出学生班级时间表

2 个答案: