在VB.NET中删除SQL语句

Question

I am new to VB.NET and as well as MySqL. I want to delete records in my database. Using,

    Dim SQLStatement As String = "DELETE name,date FROM people"
    RetrieveInfos(SQLStatement)

Where,

Public Sub RetrieveInfos(ByRef SQLStatement As String)
    Dim cmd As MySqlCommand = New MySqlCommand

    With cmd
        .CommandText = SQLStatement
        .CommandType = CommandType.Text
        .Connection = SQLConnection
        .ExecuteNonQuery()

    End With

    SQLConnection.Close()
    SQLConnection.Dispose()
End Sub

But there is an error of InvalidOperationException, I am confused. I want to delete records in my database without referencing the " WHERE number = VALUE " in order to delete the previous recorded value. Is that possible?

Any help would be appreciated. Thanks!

Answer 1

You've got a few problems:

1. You do not specify column names in the delete statement since you are deleting records.

2. Your command, should it be successfully executed, will delete every record in the people table.

3. You are closing and disposing the SQLConnection at the end of the RetrieveInfos method. If this connection is open elsewhere in your code, only the first execution of the code will work.

4. Your method should not be called Retrieve if it is deleting.

5. The command should be wrapped in a using statement

    Using cmd As MySqlCommand = New MySqlCommand With cmd .CommandText = SQLStatement .CommandType = CommandType.Text .Connection = SQLConnection .ExecuteNonQuery() End With End Using