如何在SQL Server中使用'date'數據類型

Question

我目前正在嘗試使用Visual Studio在c＃中創建一個asp.net web應用程序。我有一個頁面充當父母或孩子的註冊頁面，具體取決於您選擇的單選按鈕。註冊孩子時，您需要從三個單獨的下拉列表中輸入DOB。現在，我將DOB數據類型設置爲varchar，這意味着05/05/2005的DOB在表中保存爲'552005'。

當我的數據類型設置爲date或datetime它拋出這個錯誤：

An exception of type 'System.Data.SqlClient.SqlException' occurred in System.Data.dll but was not handled in user code Additional information: Conversion failed when converting date and/or time from character string.

這是否意味着我必須將字符串解析成一個int某處的代碼？如果是這樣，我的代碼中究竟應該如何以及在哪裏？我將包含一些截圖以及我的代碼。

提前致謝！

Showing how my form looks and how DOB currently stores in table

protected void submitBtn_Click(object sender, EventArgs e) 
{ 
    SqlConnection connect = new SqlConnection("Data Source=THEBEAST;Initial Catalog=newregDB;Integrated Security=True;Pooling=False"); 

    if (parentRadBtn.Checked) 
    { 
     if (firstNameBox.Text == "" || surnameBox.Text == "" || postcodeBox.Text == "" || teleBox.Text == "" || emailBox.Text == "" || userBox.Text == "" || passwordBox.Text == "") 
     { 
      Response.Write("<script>alert('Please ensure all fields have an entry');</script>"); 
      successLabel.Text = (""); 
      userBox.Text = ""; 
      firstNameBox.Text = ""; 
      surnameBox.Text = ""; 
      postcodeBox.Text = ""; 
      teleBox.Text = ""; 
      emailBox.Text = ""; 
      passwordBox.Text = ""; 
     } 
     else 
     { 
      SqlCommand pa = new SqlCommand("INSERT INTO parent(parentID, firstname, surname, postcode, telephone, email, password) VALUES (@parentID, @firstname, @surname, @postcode, @telephone, @email, @password)", connect); 
      pa.Parameters.AddWithValue("@parentID", userBox.Text); 
      pa.Parameters.AddWithValue("@firstname", firstNameBox.Text); 
      pa.Parameters.AddWithValue("@surname", surnameBox.Text); 
      pa.Parameters.AddWithValue("@postcode", postcodeBox.Text); 
      pa.Parameters.AddWithValue("@telephone", teleBox.Text); 
      pa.Parameters.AddWithValue("@email", emailBox.Text); 
      pa.Parameters.AddWithValue("@password", passwordBox.Text); 

      connect.Open(); 
      pa.ExecuteNonQuery(); 
      connect.Close(); 
     } 

     if (IsPostBack) 
     { 
      userBox.Text = ""; 
      firstNameBox.Text = ""; 
      surnameBox.Text = ""; 
      postcodeBox.Text = ""; 
      teleBox.Text = ""; 
      emailBox.Text = ""; 
      passwordBox.Text = ""; 
     } 
    }   
    else if (childRadBtn.Checked) 
    { 
     if (firstNameBox.Text == "" || dayDobList.Text == "" || monthDobList.Text == "" || yearDobList.Text == "" || genderList.Text == "" || userBox.Text == "" || passwordBox.Text == "") 
     { 
      Response.Write("<script>alert('Please ensure all fields have an entry');</script>"); 
      successLabel.Text = (""); 
      userBox.Text = ""; 
      firstNameBox.Text = ""; 
      dayDobList.Text = ""; 
      monthDobList.Text = ""; 
      yearDobList.Text = ""; 
      genderList.Text = ""; 
      passwordBox.Text = ""; 
     } 
     else 
     { 
      SqlCommand ca = new SqlCommand("INSERT INTO children(childID, firstname, dob, gender, password) VALUES (@childID, @firstname, @dob, @gender, @password)", connect); 
      ca.Parameters.AddWithValue("@childID", userBox.Text); 
      ca.Parameters.AddWithValue("@firstname", firstNameBox.Text); 
      ca.Parameters.AddWithValue("@dob", dayDobList.Text + monthDobList.Text + yearDobList.Text); 
      ca.Parameters.AddWithValue("@gender", genderList.Text); 
      ca.Parameters.AddWithValue("@password", passwordBox.Text); 

      connect.Open(); 
      ca.ExecuteNonQuery(); 
      connect.Close(); 
     } 

     if (IsPostBack) 
     { 
      userBox.Text = ""; 
      firstNameBox.Text = ""; 
      dayDobList.Text = ""; 
      monthDobList.Text = ""; 
      yearDobList.Text = ""; 
      genderList.Text = ""; 
      passwordBox.Text = ""; 
     }    
    } 
} 

Answer 1

你的問題是，你必須與舊格式'552005'您的表中的一些數據，所以當你想改變列類型，你會得到錯誤。所以你有兩種選擇：

1-從該表中刪除任何東西，更改列類型並開始保存日期爲datetime或datetime2。

2-將所有當前數據轉換爲日期字符串，例如。 '05/05/2005 00:00:00'，然後將列類型更改爲datetime。

UPDATE：

也不要忘記爲數據類型添加到您的SqlParameters：

SqlParameter dob = new SqlParameter("@sinceDateTime", SqlDbType.DateTime); 
dob.Value = new DateTime(Int32.Parse(yearDobList.Text), Int32.Parse(monthDobList.Text), Int32.Parse(dayDobList.Text)); 
ca.Parameters.Add(dob); 

Answer 2

需要一個日期，讓日期：

new DateTime(int.Parse(dayDobList.Text), 
      int.Parse(monthDobList.Text), 
      int.Parse(yearDobList.Text))