vb.net中向数据库中定时添加数据？紧急求助！

[wfl_1000]

我在程序一个按钮中中向数据库中添加了表，并且想在另一个按钮中向表中添加数据，
点击一下添加一次，现在的问题是只可以添加一次数据，再点击时提示表已经存在，
请问怎解决？麻烦各位，情况紧急！
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

strYear = System.DateTime.Now.Year.ToString()
strMonth = System.DateTime.Now.Month.ToString()
strDate = System.DateTime.Now.Day.ToString()
theName = "Table" + strYear + strMonth + strDate

'Dim sql As String = Nothing
'Dim MyInsert As String = Nothing
conn = New SqlConnection(ConnectionString)
If conn.State = ConnectionState.Open Then
conn.Close()
End If
conn.ConnectionString = ConnectionString
conn.Open()
sql = "CREATE TABLE " + theName + "" + "(myid NVARCHAR(50)," + "myname NVARCHAR(50) NOT Null,myaddress NVARCHAR(50))"
cmd = New SqlCommand(sql, conn)
Button2.Enabled = True

End Sub

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
conn = New SqlConnection(ConnectionString)
If conn.State = ConnectionState.Open Then
conn.Close()
End If
conn.ConnectionString = ConnectionString
conn.Open()
cmd = New SqlCommand(sql, conn)
Try
cmd.ExecuteNonQuery()
'添加记录
MyInsert = "INSERT INTO " + theName + "(myid,myname,myaddress)values(01,'王富力','dizhi')"
cmd = New SqlCommand(MyInsert, conn)
cmd.ExecuteNonQuery()
Catch ex As Exception
MessageBox.Show(ex.Message.ToString())
End Try
End Sub

[ojekleen]

你是某个字段有设唯一列吧。。。然后重复插入相同的数据就出错吧？

[tjficcbw]

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click 

        strYear = System.DateTime.Now.Year.ToString() 
        strMonth = System.DateTime.Now.Month.ToString() 
        strDate = System.DateTime.Now.Day.ToString() 
        theName = "Table" + strYear + strMonth + strDate 

        'Dim sql As String = Nothing 
        'Dim MyInsert As String = Nothing 
        conn = New SqlConnection(ConnectionString) 
        If conn.State = ConnectionState.Open Then 
            conn.Close() 
        End If 
        conn.ConnectionString = ConnectionString 
        conn.Open() 
        sql = "CREATE TABLE " + theName + "" + "(myid NVARCHAR(50)," + "myname NVARCHAR(50) NOT Null,myaddress NVARCHAR(50))" 
        cmd = New SqlCommand(sql, conn) '这的SQL是建立表的语句 
        Button2.Enabled = True 

    End Sub 

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click 
        conn = New SqlConnection(ConnectionString) 
        If conn.State = ConnectionState.Open Then 
            conn.Close() 
        End If 
        conn.ConnectionString = ConnectionString 
        conn.Open() 
        cmd = New SqlCommand(sql, conn) '这的SQL是建立表的语句 
        Try 
            cmd.ExecuteNonQuery() '这是执行建立表的语句 
            '添加记录 
            MyInsert = "INSERT INTO " + theName + "(myid,myname,myaddress)values(01,'王富力','dizhi')" 
            cmd = New SqlCommand(MyInsert, conn) '这的MyInsert是插入的语句 
            cmd.ExecuteNonQuery() '这是执行插入的语句
        Catch ex As Exception 
            MessageBox.Show(ex.Message.ToString()) 
        End Try 

你的按钮1和2全有建立表的语句，这不可能总建立一个表，
表建立一次就行了，不要每次建立一次这样不行，

[wfl_1000]

怎么写才是建立一次呢？请指教！

[Fibona]

建表的时候加上判断,

string sql=@"
if not exists (select 1
from sysobjects
where id = object_id('"+tablename+@"')
and type = 'U')
begin
create table tablename(

(myid NVARCHAR(50),myname NVARCHAR(50) NOT Null,myaddress NVARCHAR(50))
);

end ";

[Fibona]

string sql=@" 
if not exists (select 1 
            from  sysobjects 
          where  id = object_id('"+tablename+@"') 
            and  type = 'U') 
begin 
  create table tablename( 

myid NVARCHAR(50),myname NVARCHAR(50) NOT Null,myaddress NVARCHAR(50) 
); 

end "; 

[wfl_1000]

vb.net 代码怎么写？

[noenoughmemory]

友情up

[noenoughmemory]

友情up

[noenoughmemory]

不懂，up

[gbjgg]

不懂，up

[wfl_1000]

求助中！

[tjficcbw]

就是在按钮1建立表，按钮2就只插入，不建立表，这样不就行了，
为什么每次在插入时要先建立表呢，