如何查詢與外鍵中特定名稱匹配的數據庫？

我在我的數據庫Student和Subject中有兩個表。我在StudentID（學生主鍵）和該主題的外鍵之間建立了關係。如何查詢與外鍵中特定名稱匹配的數據庫？

下面是我的主題數據列表：

如何選擇所有的外鍵匹配的數據（StudentID爲主題），例如：2011017997顯示courseno，coursedecription，臺，日，開始時間等。

我想使用會話在下一頁顯示我的主題數據作爲Gridview。

這背後是我的aspx代碼：

string query = null; 
    string subjectquery = null; 
    int rowcounter = 0; 
    private DataSet studentData; 
    private DataSet subjectData; 
    private DataTable subjectTable; 

    protected void Button1_Click(object sender, EventArgs e) 
    { 
     //Connection String 
     connector.ConnectionString = "Data Source=keith;Initial Catalog=SAD;Integrated Security=True"; 

     //String decleration 
     string username = (this.UserName.Value); 
     string pass = (this.Password.Value); 

     //query database from sql server management studio for student 
     query = "select studentid,password,firstname,lastname,course,year from student"; 

     //query database from sql server management studio for subject 
     subjectquery = "select CourseNo,CourseDescription,Units,Day,StartTime,EndTime,Room from subject"; 

     //execute query for student 
     studentData = connector.ExecuteQuery(query); 

     //execute query for subject 
     subjectData = connector.ExecuteQuery(subjectquery); 


     for (;;) 
     { 
      //string decleration and getting each rows of the Student database 
      string userid = studentData.Tables[0].Rows[rowcounter]["StudentID"].ToString(); 
      string password = studentData.Tables[0].Rows[rowcounter]["Password"].ToString(); 
      string firstname = studentData.Tables[0].Rows[rowcounter]["FirstName"].ToString(); 
      string lastname = studentData.Tables[0].Rows[rowcounter]["LastName"].ToString(); 
      string course = studentData.Tables[0].Rows[rowcounter]["Course"].ToString(); 
      string year = studentData.Tables[0].Rows[rowcounter]["Year"].ToString(); 

      //get all subject data rows and store it into DataTable 
      subjectTable = subjectData.Tables[0]; 

      //Username and Password are correct 
      if ((username == userid) && (pass == password)) 
      { 
       Session["login"] = userid; 
       Session["firstname"] = firstname; 
       Session["lastname"] = lastname; 
       Session["course"] = course; 
       Session["year"] = year; 
       Session["Subjects"] = subjectTable; 
       Response.Redirect("StudentPage.aspx", true); 
       break; 
      } 
      //empty username and password 
      else if (((username == "") && (pass == "")) || ((userid == null) && (password == null))) 
      { 
       Response.Write("<script language=javascript>alert('Username and password must have input value. Try again');</script>"); 
       break; 
      } 
      //username is invalid and password is correct ; username is correct and password is invalid 
      else if (((username != userid) && (pass == password)) || ((username == userid) && (pass != password))) 
      { 
       Response.Write("<script language=javascript>alert('Username and password does not match. Try again');</script>"); 
       break; 
      } 
      else 
      { 
       rowcounter++; 
      } 
     } 
    }

當程序顯示結果的主題的所有的數據顯示，但不能的studentID「2011017997」的數據。

我想我的問題是查詢，這樣的：

//query database from sql server management studio for subject 
      subjectquery = "select CourseNo,CourseDescription,Units,Day,StartTime,EndTime,Room from subject";

，這是我在會議顯示我的數據表：

//execute query for subject 
      subjectData = connector.ExecuteQuery(subjectquery); 
//get all subject data rows and store it into DataTable 
       subjectTable = subjectData.Tables[0]; 
Session["Subjects"] = subjectTable;

顯示在另一個使用的GridView對象數據的代碼頁碼：

//Subject Data 
       subjectdata.DataSource = Session["Subjects"]; 
       subjectdata.DataBind();

我該如何比較或僅僅顯示以下內容與以下StudentID = 2011017997匹配的cts？

來源

2015-09-13 laurence keith albano

試試這個！

subjectquery = "select * from subject where StudentID=2011017997";

來源

2015-09-13 11:34:37 boyshot17

這是一個很好的但它會顯示所有列名稱，包括studentid和teacherid。我想到了這樣的事情： subjectquery =「select CourseNo，CourseDescription，Units，Day，StartTime，EndTime，Room from subject where studentid = 2011017997」; –

是的，選擇*表示顯示錶中的所有列，您可以將其更改爲您喜歡的。希望我的回答對你有幫助！ – boyshot17

我的問題，我的回答是？哈哈反正這裏是我的問題的正確查詢。感謝Idea @ boyshot17。

//Get the value for input username 
string username = (this.UserName.Value); 

//query database from sql server management studio for subject 
subjectquery = "select CourseNo,CourseDescription,Units,Day,StartTime,EndTime,Room from subject where studentid = " + username + "";

來源

2015-09-13 11:50:01

如何查詢與外鍵中特定名稱匹配的數據庫？

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