使用存储过程检查SQL Server数据库中是否已存在行

我插入了两行具有相同内容的表，但是用于搜索现有数据的代码没有返回所需的结果

这是我的VB.Net代码：

Private Sub BtnSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnSave.Click

    Try

If DateTimePicker1.Value.Date >= DateTime.Parse(TxtDateFrom.Text) And DateTimePicker1.Value.Date <= DateTime.Parse(TxtDateTo.Text) Then


    Dim cmd1 As New SqlCommand
            cmd1 = New SqlCommand("check_sched", connection)
            cmd1.CommandType = CommandType.StoredProcedure
            Dim rd As SqlDataReader
            cmd1.Parameters.AddWithValue("@empid", Label17.Text)
            cmd1.Parameters.AddWithValue("@datesched", DateTimePicker1.Value.Date)
            cmd1.Parameters.AddWithValue("@timefrom", TimePicker1.Text)
            cmd1.Parameters.AddWithValue("@timeto", TimePicker1.Text)
            rd = cmd1.ExecuteReader()


            If rd.HasRows Then

                MsgBox("Employee already assigned a job for the particular time period", MsgBoxStyle.Information, "Change Time Period")

            Else

                Dim cmd As New SqlCommand
                cmd = New SqlCommand("insert_schedule1", connection)
                cmd.CommandType = CommandType.StoredProcedure
                cmd.Parameters.Add("@actid", SqlDbType.Int).Value = Label2.Text
                cmd.Parameters.Add("@activity", SqlDbType.NVarChar).Value = CmbActivity.Text
                cmd.Parameters.Add("@serviceid", SqlDbType.Int).Value = Label14.Text
                cmd.Parameters.Add("@servicename", SqlDbType.NVarChar).Value = TxtServiceType.Text
                cmd.Parameters.Add("@pdatefrom", SqlDbType.NVarChar).Value = TxtDateFrom.Text
                cmd.Parameters.Add("@pdateto", SqlDbType.NVarChar).Value = TxtDateTo.Text
                cmd.Parameters.Add("@deptname", SqlDbType.NVarChar).Value = Label16.Text
                cmd.Parameters.Add("@emp", SqlDbType.NVarChar).Value = CmbEmp.Text
                cmd.Parameters.Add("@empid", SqlDbType.Int).Value = Label17.Text
                cmd.Parameters.Add("@datesched", SqlDbType.DateTime).Value = myDate1
                cmd.Parameters.Add("@timefrom", SqlDbType.Time).Value = TimePicker1.Value.TimeOfDay
                cmd.Parameters.Add("@timeto", SqlDbType.Time).Value = TimePicker2.Value.TimeOfDay
                cmd.Parameters.Add("@status", SqlDbType.Int).Value = "1"
                cmd.ExecuteNonQuery()
                MsgBox("Scheduled Successfully", MsgBoxStyle.Information, "Task Schedule")
                CmbActivity.Text = ""
                TxtServiceType.Text = ""
                TxtDateFrom.Text = ""
                TxtDateTo.Text = ""
                'CmbSactivity.Text = ""
                CmbEmp.Text = ""
                DateTimePicker1.Text = Now
                TimePicker1.Text = TimeOfDay
                TimePicker2.Text = TimeOfDay
            End If
        Else
            MsgBox("Please select a date within the duration", MsgBoxStyle.Information, "Invalid Date")
        End If

    Catch ex As Exception
        MessageBox.Show(ex.Message)
    End Try
End Sub

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您的检查计划对@timeFrom和@timeTo字段都使用TimePicker1值，而insert分别使用TimePicker1和TimePicker2。这会导致您的支票看错日期

---

为了避免将来出现此问题并更容易找到这些错误，请尝试重构名称以匹配它们的用途，例如fromTimePicker和toTimePicker。

您的检查计划对@timeFrom和@timeTo字段使用TimePicker1值，而insert分别使用TimePicker1和TimePicker2。这会导致您的支票看错日期

---

为了避免将来出现此问题并更容易找到这些错误，请尝试重构名称以匹配它们的用途，例如fromTimePicker和toTimePicker。

请提供表结构和所需结果。使用表定义编辑问题。现在面临的问题是此代码未显示任何错误，但是如果我输入了两个相同empid的字段datesched，timefrom和timeto应显示员工在该时间段内已分配给另一项工作的消息框。相反，数据会再次添加到数据库中，显示消息框计划成功。请提供表结构和所需结果。使用表定义编辑问题。我现在面临的问题是代码没有显示任何错误，但如果我输入了两个具有相同empid、datesched、timefrom和timeto的字段，则应显示员工在该时间段已分配给其他工作的消息框。相反，数据会再次添加到数据库中，显示消息框Scheduled Successfully，我建议在INSERT存储过程中检查员工是否在该时间段内已被分配到另一个工作，并让其返回指示成功或失败的位输出参数。此外，我建议在INSERT存储过程中检查员工是否在该时间段内已被分配到另一个工作，并让它返回一个指示成功或失败的位输出参数。

create procedure check_sched
    @empid int,
    @datesched datetime,
    @timefrom datetime,
    @timeto datetime
as 
begin
    SELECT * 
    FROM tbl_schedule 
    WHERE empid = @empid 
      AND datesched = @datesched 
      AND timefrom >= @timefrom 
      AND timeto <= @timeto
end

CREATE TABLE [dbo].[tbl_schedule]
(   
     [actid] [int] NULL,    
     [activity] [nvarchar](350) NULL,   
     [serviceid] [int] NULL,    
     [servicename] [nvarchar](50) NULL,     
     [pdatefrom] [nvarchar](50) NULL,   
     [pdateto] [nvarchar](50) NULL,     
     [sactid] [int] NULL,   
     [sactivity] [nvarchar](500) NULL,  
     [deptname] [nvarchar](150) NULL,   
     [emp] [nvarchar](150) NULL,    
     [empid] [int] NULL,    
     [datesched] [datetime] NULL,   
     [timefrom] [datetime] NULL,    
     [timeto] [datetime] NULL,
     [actimefrom] [datetime] NULL,  
     [actimeto] [datetime] NULL,
     [completed] [int] NULL,    
     [status] [int] NULL 
) ON [PRIMARY]