[sql] 매개 변수가있는 SQL 쿼리는 어떻게 생성합니까? 왜해야합니까?

다음은 SQL로 시작하는 간단한 클래스이며 여기에서 빌드하고 클래스에 추가 할 수 있습니다.

MySQL

Public Class mysql

    'Connection string for mysql
    Public SQLSource As String = "Server=123.456.789.123;userid=someuser;password=somesecurepassword;database=somedefaultdatabase;"

    'database connection classes

    Private DBcon As New MySqlConnection
    Private SQLcmd As MySqlCommand
    Public DBDA As New MySqlDataAdapter
    Public DBDT As New DataTable
    Public BindSource As New BindingSource
    ' parameters
    Public Params As New List(Of MySqlParameter)

    ' some stats
    Public RecordCount As Integer
    Public Exception As String

    Function ExecScalar(SQLQuery As String) As Long
        Dim theID As Long
        DBcon.ConnectionString = SQLSource
        Try
            DBcon.Open()
            SQLcmd = New MySqlCommand(SQLQuery, DBcon)
            'loads params into the query
            Params.ForEach(Sub(p) SQLcmd.Parameters.AddWithValue(p.ParameterName, p.Value))

            'or like this is also good
            'For Each p As MySqlParameter In Params
            ' SQLcmd.Parameters.AddWithValue(p.ParameterName, p.Value)
            ' Next
            ' clears params
            Params.Clear()
            'return the Id of the last insert or result of other query
            theID = Convert.ToInt32(SQLcmd.ExecuteScalar())
            DBcon.Close()

        Catch ex As MySqlException
            Exception = ex.Message
            theID = -1
        Finally
            DBcon.Dispose()
        End Try
        ExecScalar = theID
    End Function

    Sub ExecQuery(SQLQuery As String)

        DBcon.ConnectionString = SQLSource
        Try
            DBcon.Open()
            SQLcmd = New MySqlCommand(SQLQuery, DBcon)
            'loads params into the query
            Params.ForEach(Sub(p) SQLcmd.Parameters.AddWithValue(p.ParameterName, p.Value))

            'or like this is also good
            'For Each p As MySqlParameter In Params
            ' SQLcmd.Parameters.AddWithValue(p.ParameterName, p.Value)
            ' Next
            ' clears params

            Params.Clear()
            DBDA.SelectCommand = SQLcmd
            DBDA.Update(DBDT)
            DBDA.Fill(DBDT)
            BindSource.DataSource = DBDT  ' DBDT will contain your database table with your records
            DBcon.Close()
        Catch ex As MySqlException
            Exception = ex.Message
        Finally
            DBcon.Dispose()
        End Try
    End Sub
    ' add parameters to the list
    Public Sub AddParam(Name As String, Value As Object)
        Dim NewParam As New MySqlParameter(Name, Value)
        Params.Add(NewParam)
    End Sub
End Class

MS SQL / Express

Public Class MSSQLDB
    ' CREATE YOUR DB CONNECTION
    'Change the datasource
    Public SQLSource As String = "Data Source=someserver\sqlexpress;Integrated Security=True"
    Private DBCon As New SqlConnection(SQLSource)

    ' PREPARE DB COMMAND
    Private DBCmd As SqlCommand

    ' DB DATA
    Public DBDA As SqlDataAdapter
    Public DBDT As DataTable

    ' QUERY PARAMETERS
    Public Params As New List(Of SqlParameter)

    ' QUERY STATISTICS
    Public RecordCount As Integer
    Public Exception As String

    Public Sub ExecQuery(Query As String, Optional ByVal RunScalar As Boolean = False, Optional ByRef NewID As Long = -1)
        ' RESET QUERY STATS
        RecordCount = 0
        Exception = ""
        Dim RunScalar As Boolean = False

        Try
            ' OPEN A CONNECTION
            DBCon.Open()

            ' CREATE DB COMMAND
            DBCmd = New SqlCommand(Query, DBCon)

            ' LOAD PARAMS INTO DB COMMAND
            Params.ForEach(Sub(p) DBCmd.Parameters.Add(p))

            ' CLEAR PARAMS LIST
            Params.Clear()

            ' EXECUTE COMMAND & FILL DATATABLE
            If RunScalar = True Then
                NewID = DBCmd.ExecuteScalar()
            End If
            DBDT = New DataTable
            DBDA = New SqlDataAdapter(DBCmd)
            RecordCount = DBDA.Fill(DBDT)
        Catch ex As Exception
            Exception = ex.Message
        End Try


        ' CLOSE YOUR CONNECTION
        If DBCon.State = ConnectionState.Open Then DBCon.Close()
    End Sub

    ' INCLUDE QUERY & COMMAND PARAMETERS
    Public Sub AddParam(Name As String, Value As Object)
        Dim NewParam As New SqlParameter(Name, Value)
        Params.Add(NewParam)
    End Sub
End Class

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