數據庫查詢執行

我在C＃中有一個應用程序，數據庫是sqlite（.db3）。我有2個功能。數據庫查詢執行

String sConnectionString = "Data Source=mydb.db3;Version=3;Password=123456;"; 
private void longitudinalProfileToolStripMenuItem_Click(object sender, EventArgs e) 
{ 
    saveProject(iProjectID); 
    computeArea(iProjectID); 
} 

public int saveProject(iProjectID) 
{ 
    SQLiteCommand sqlite_cmd; 
    SQLiteCommand sqlite_cmd_PostWork; 
    SQLiteCommand sqlite_cmd_Design; 
    sqlite_conn = new SQLiteConnection(sConnectionString); 
    sqlite_cmd.CommandText = "Delete from prework where pid = " + iProjectID + ";"; 
    sqlite_cmd.ExecuteNonQuery(); 
    sqlite_cmd.CommandText = "Insert into prework (pid, chainage, date) values (" + iProjectID + "," + fChainagePostwork + ",'" + dateTimePicker1.Value.Date.ToString("yyyy-MM-dd") + "');"; 
    sqlite_cmd.ExecuteNonQuery(); 
    sqlite_conn.Close(); 
return 1; 
} 

public int computeArea(iProjectID) 
{ 
    SQLiteCommand sqlite_cmd; 
    SQLiteCommand sqlite_cmd_PostWork; 
    SQLiteCommand sqlite_cmd_Design; 
    sqlite_conn = new SQLiteConnection(sConnectionString); 
    sqlite_cmd.CommandText = "Delete from postwork where pid = " + iProjectID + ";"; 
    sqlite_cmd.ExecuteNonQuery(); 
    sqlite_cmd.CommandText = "Insert into postwork (pid, chainage, date) values (" + iProjectID + "," + fChainagePostwork + ",'" + dateTimePicker1.Value.Date.ToString("yyyy-MM-dd") + "');"; 
    sqlite_cmd.ExecuteNonQuery(); 
    sqlite_conn.Close(); 
return 1; 
}

saveProject（）函數可以正常工作。但在computeArea（）函數中，查詢不顯示任何錯誤，但數據庫/表不更新/插入/刪除。

如果我第二次調用longitudinalProfileToolStripMenuItem_Click（object sender，EventArgs e），那麼它工作正常。

但在以前的時間裏，它正常工作。問題是什麼？

來源

2017-01-02 Rakib

什麼是這兩個表的架構？您正在使用字符串連接，除了向您公開SQL注入攻擊外，還會因類型轉換錯誤而中斷連接。如果一個表需要一個字符串，另一個表需要一個浮點數，如果您嘗試輸入帶有意外小數點分隔符的字符串，則第二個表會失敗。 –

順便說一句你的代碼是無效的C＃代碼。 'computeArea（iProjectID）'不是有效的函數聲明。實際編譯的郵政編碼，包括任何可能隱藏錯誤的異常處理代碼 –

實際上，如果我單獨調用第二個函數，第二個函數將正常工作。如果我以同樣的方式調用問題，那麼它不會顯示任何錯誤。 @PanagiotisKanavos – Rakib

-2

你可以使用「使用塊」這樣，

String sConnectionString = "Data Source=mydb.db3;Version=3;Password=123456;"; 
private void longitudinalProfileToolStripMenuItem_Click(object sender, EventArgs e) 
{ 
    saveProject(iProjectID); 
    computeArea(iProjectID); 
} 

saveProject(iProjectID) 
{ 
    SQLiteCommand sqlite_cmd; 
    SQLiteCommand sqlite_cmd_PostWork; 
    SQLiteCommand sqlite_cmd_Design; 
    using (sqlite_conn = new SQLiteConnection(sConnectionString)) 
    { 
     sqlite_conn.Open(); 
     sqlite_cmd.CommandText = "Delete from prework where pid = " + iProjectID + ";"; 
     sqlite_cmd.ExecuteNonQuery(); 
     sqlite_cmd.CommandText = "Insert into prework (pid, chainage, date) values (" + iProjectID + "," + fChainagePostwork + ",'" + dateTimePicker1.Value.Date.ToString("yyyy-MM-dd") + "');"; 
     sqlite_cmd.ExecuteNonQuery(); 
    } 
} 

computeArea(iProjectID) 
{ 
    SQLiteCommand sqlite_cmd; 
    SQLiteCommand sqlite_cmd_PostWork; 
    SQLiteCommand sqlite_cmd_Design; 

    using (sqlite_conn = new SQLiteConnection(sConnectionString)) 
    { 
     sqlite_conn.Open(); 
     sqlite_cmd.CommandText = "Delete from postwork where pid = " + iProjectID + ";"; 
     sqlite_cmd.ExecuteNonQuery(); 
     sqlite_cmd.CommandText = "Insert into postwork (pid, chainage, date) values (" + iProjectID + "," + fChainagePostwork + ",'" + dateTimePicker1.Value.Date.ToString("yyyy-MM-dd") + "');"; 
     sqlite_cmd.ExecuteNonQuery(); 
    } 
}

來源

2017-01-02 10:11:31

這是如何解決他的實際問題？ –

顯示錯誤「數據庫未打開」錯誤。 – Rakib

我加了「sqlite_conn.Open（）;」 –

數據庫查詢執行

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