【正文】 () (()) 第四章 系統(tǒng)實現(xiàn)與驗證 17 Exit Sub End If If (type) = 1 Then 39。管理登錄 () (()) Exit Sub End If 為一圖片控件， 為用戶登錄 菜單，添加 3 個LinkButton 控件，分學(xué)生、教師、管理員身份， 為登錄介紹。在登錄頁面對應(yīng)的地方輸入用戶名、密碼，確認后登錄。登錄界面如圖 所示。教師、管理員的也相同。登錄界面如圖 所示。 2）退出系統(tǒng)中代碼如下： ()39。 3）修改密碼中代碼如下： If Then () Else Dim db As New dbaccess (Session(type)) (id, Session(user)) (oldpwd, ) (pwd, ) Dim temp As String temp = Session(type) (type, ) (changepwd) If () Then () Else () End If End If 教師模塊功能 教師登陸也同樣傳遞 session 值，將教工號和 type 值保留以備調(diào)用不同的用戶控件。登錄界面如圖 所示。系統(tǒng)還原調(diào)用存儲過程 hy，備份調(diào)用存儲過程 bf，添加、修改、刪除課程信息分別調(diào)用存儲過程 ins_c、 del_c、 course_update， 添加、修改、刪除學(xué)生信息分別調(diào)用存儲過程 ins_s、 del_s、 student _update， 添加、修改、刪除課程信息分別調(diào)用存儲過程 ins_t、 del_t、 teacher_update。綁定班級信息 = (0).Columns(1).ToString 39。值為班級號 () 第四章 系統(tǒng)實現(xiàn)與驗證 23 End If submit_Click 中的代碼 If And Then Dim db As New dbaccess (sid, ) (pwd, ) (sname, ) (sex, ) (gradeid, ) (telep, ) (ins_s) If Then = insert success ! Else = insert failure! record may exists ! = = = = = End If Else = 學(xué)號或密碼不能為空 ! End If 存儲過程 為了提高效率，使代碼簡單，大量使用了存儲過程。cc39。KILL 39。ok39。 本程序中編寫了一個類，供各摸塊使用，代碼如下： Imports Imports Imports Public Class dbaccess 39。如果返回的第一個表不為空 ,則為 1,反之為 0 Public para As New ListDictionary 39。database= + db + 。pwd=csf) Dim m As New SqlCommand 第四章 系統(tǒng)實現(xiàn)與驗證 26 Dim adp As New SqlDataAdapter(m) = conn = = procNAME () Dim myDE As DictionaryEntry 39。參數(shù)已無用 ,回收空間 If Not (ds Is Nothing) Then 39。如果有結(jié)果返回，則為真 End If Else retok = 0 39。 由于本身能力的局限性，所以所編 寫的代碼，即使經(jīng)過反復(fù)檢查也難免出錯，所以在本階段力求使用有限的時間找出盡可能多的錯誤，力求系統(tǒng)盡量正確。列舉出幾個驗證過程如表 ， ， ， 所示。加載測試工作貫穿于程序測試工作的全過程，整個錄入、修改、刪除、查詢、處理工作均可視為對數(shù)據(jù)庫的加載測試 工作。 2）主鍵的個數(shù)越少越好。 3）字段的個數(shù)越少越好。數(shù)據(jù)庫的設(shè)計中，如何處理多對多的關(guān)系和如何設(shè)計主鍵，是兩個有著較大難度、需要重點考慮的問題?；緦崿F(xiàn)了學(xué)生選課系統(tǒng)所期望的功能，驗證也得到了預(yù)期的效果。例如一開始我使用的是框架結(jié)構(gòu)，由于有許多的局限性，又想使用 中的頁面繼承，也沒有得到解決，最后使用 table 和 panel 控件解決了同一頁面鏈接不同的頁面。 在整個設(shè)計階段感受最為深刻的是掌握學(xué)習(xí)的方式和解決問題的方法。 參考文獻 30 參考文獻 [1] 羅斌 . 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Visual Basic數(shù)據(jù)庫開發(fā)典型模塊與實例精講 .電子工業(yè)出版社 , 第四章 系統(tǒng)實現(xiàn)與驗證 31 致謝 歷經(jīng)兩個月的努力，在老師的悉心指導(dǎo)下，我們終于順利完成了畢業(yè)設(shè)計。從而讓我們對自己有了一個更加準確的認識，對專業(yè)知識有了一個更加融會貫通的理解，更為 下一階段的學(xué)習(xí)打下了一個重要的基礎(chǔ)。 lights far to port and starboard. Sea Shepherd ploughed on towards Miami. 4. All ashore Susan opened her arms, as if to greet a longlost friend. The sun had returnednot the halfhearted, hideandseek sun of recent wee ks. No, this was the real thing, pure gold pouring out of a perfect sky. She felt the warmth seeping deep into her skin. Slowly the shore floated forward to meet them, or so it seemed. Miami! Without asking, she helped herself to the binoculars hanging round Gary39。s binoculars. Both were shading their eyes. The sun shone everywhere, from above and from below, sparking silver on the water, teeming and gleaming like a shoal of surfacing fish ... Warm enough for you? Ben Bellingham stood between them. Temperature39。s a pelican. Ben pointed. A brown pelican, quite mon around the Florida c oast. People love watching their antics. The big bird, which reminded Gary of a pterodactyl, was ma king a reconnaissance flight parallel to Sea Shepherd. Suddenly the pelican plunged. A splash, a quic k gobbling movement, and another fat fish was stored away in the bird39。s beak. Must have a nest nearby, mented Bellingham. He shook himself. Well, gotta be going. I39。s 910 local time, five hours behind England. The bearlike naturalist shambled away. To think Susan had once felt shy, almost frightened of meeting him! She sensed, rather than saw, a new presence and peeked sideways. It was Yves. He was draped over the ship39。s eyes took in the scene farther along the deck. Ah, that was it. Vanessa. Wearing a polka dot sunsuit that showed off her slender figure and shapely legs. Talking to Johnny Masterson, the handsome heman security officer, in khaki shirt and shorts. Obviously enjoying themselves. Poor Yves! The pelican had resumed its patrol. Susan inched nearer to Yves. Hello, she said lightly. See the pelican? Betcha it catches something in a minute? Yves lifted his head. Immediately the pelican obliged with a spectacular swoop. Told you, didn39。s nothin39。t want to take him anywhere. Ling [following Mulan]: Ping, we have to fight! Mulan: No we don