?Imports System.Data.OleDb
Imports System.Data
Imports System.Xml

'****************************************************************
'   DHU
'   Copyright (c) 2006 DHU.
'****************************************************************
'****************************************************************
'ファイル名   : C_SQLHelper.vb
'項目名稱     : BAシステム
'機能概要　   :	共通処理
'               The SqlHelper class is intended to encapsulate high performance, scalable best practices for 
'               common uses of SqlClient.
'作成者       : WeiZY
'確認者       : WeiZY
'編集日付     : 2006.07.26
'修正者       : WeiZY
'修正日付     : 2006.8.30
'修正內(nèi)容概要 :
'****************************************************************

' ===============================================================================
' Release history
' VERSION	DESCRIPTION
'   2.0	Added support for FillDataset, UpdateDataset and "Param" helper methods
'
' ===============================================================================

Public NotInheritable Class SqlHelper

#Region "private utility methods & constructors"

    ' Since this class provides only static methods, make the default constructor private to prevent 
    ' instances from being created with "new SqlHelper()".
    Private Sub New()
    End Sub     ' New

    ' This method is used to attach array of oledbParameters to a oledbCommand.
    ' This method will assign a value of DbNull to any parameter with a direction of
    ' InputOutput and a value of null.  
    ' This behavior will prevent default values from being used, but
    ' this will be the less common case than an intended pure output parameter (derived as InputOutput)
    ' where the user provided no input value.
    ' Parameters:
    ' -command - The command to which the parameters will be added
    ' -commandParameters - an array of oledbParameters to be added to command
    Private Shared Sub AttachParameters(ByVal command As oledbCommand, ByVal commandParameters() As oledbParameter)
        If (command Is Nothing) Then Throw New ArgumentNullException("command")
        If (Not commandParameters Is Nothing) Then
            Dim p As oledbParameter
            For Each p In commandParameters
                If (Not p Is Nothing) Then
                    ' Check for derived output value with no value assigned
                    If (p.Direction = ParameterDirection.InputOutput OrElse p.Direction = ParameterDirection.Input) AndAlso p.Value Is Nothing Then
                        p.Value = DBNull.Value
                    End If
                    command.Parameters.Add(p)
                End If
            Next p
        End If
    End Sub     ' AttachParameters

    ' This method assigns dataRow column values to an array of oledbParameters.
    ' Parameters:
    ' -commandParameters: Array of oledbParameters to be assigned values
    ' -dataRow: the dataRow used to hold the stored procedure' s parameter values
    Private Overloads Shared Sub AssignParameterValues(ByVal commandParameters() As oledbParameter, ByVal dataRow As DataRow)

        If commandParameters Is Nothing OrElse dataRow Is Nothing Then
            ' Do nothing if we get no data    
            Exit Sub
        End If

        ' Set the parameters values
        Dim commandParameter As oledbParameter
        Dim i As Integer
        For Each commandParameter In commandParameters
            ' Check the parameter name
            If (commandParameter.ParameterName Is Nothing OrElse commandParameter.ParameterName.Length <= 1) Then
                Throw New Exception(String.Format("Please provide a valid parameter name on the parameter #{0}, the ParameterName property has the following value: ' {1}' .", i, commandParameter.ParameterName))
            End If
            If dataRow.Table.Columns.IndexOf(commandParameter.ParameterName.Substring(1)) <> -1 Then
                commandParameter.Value = dataRow(commandParameter.ParameterName.Substring(1))
            End If
            i = i + 1
        Next
    End Sub

    ' This method assigns an array of values to an array of oledbParameters.
    ' Parameters:
    ' -commandParameters - array of oledbParameters to be assigned values
    ' -array of objects holding the values to be assigned
    Private Overloads Shared Sub AssignParameterValues(ByVal commandParameters() As oledbParameter, ByVal parameterValues() As Object)

        Dim i As Integer
        Dim j As Integer

        If (commandParameters Is Nothing) AndAlso (parameterValues Is Nothing) Then
            ' Do nothing if we get no data
            Return
        End If

        ' We must have the same number of values as we pave parameters to put them in
        If commandParameters.Length <> parameterValues.Length Then
            Throw New ArgumentException("Parameter count does not match Parameter Value count.")
        End If

        ' Value array
        j = commandParameters.Length - 1
        For i = 0 To j
            ' If the current array value derives from IDbDataParameter, then assign its Value property
            If TypeOf parameterValues(i) Is IDbDataParameter Then
                Dim paramInstance As IDbDataParameter = CType(parameterValues(i), IDbDataParameter)
                If (paramInstance.Value Is Nothing) Then
                    commandParameters(i).Value = DBNull.Value
                Else
                    commandParameters(i).Value = paramInstance.Value
                End If
            ElseIf (parameterValues(i) Is Nothing) Then
                commandParameters(i).Value = DBNull.Value
            Else
                commandParameters(i).Value = parameterValues(i)
            End If
        Next
    End Sub     ' AssignParameterValues

    ' This method opens (if necessary) and assigns a connection, transaction, command type and parameters 
    ' to the provided command.
    ' Parameters:
    ' -command - the oledbCommand to be prepared
    ' -connection - a valid oledbconnection, on which to execute this command
    ' -transaction - a valid oledbTransaction, or ' null' 
    ' -commandType - the CommandType (stored procedure, text, etc.)
    ' -commandText - the stored procedure name or T-SQL command
    ' -commandParameters - an array of oledbParameters to be associated with the command or ' null' if no parameters are required
    Private Shared Sub PrepareCommand(ByVal command As oledbCommand, _
      ByVal connection As oledbconnection, _
      ByVal transaction As oledbTransaction, _
      ByVal commandType As CommandType, _
      ByVal commandText As String, _
      ByVal commandParameters() As oledbParameter, ByRef mustCloseConnection As Boolean)

        If (command Is Nothing) Then Throw New ArgumentNullException("command")
        If (commandText Is Nothing OrElse commandText.Length = 0) Then Throw New ArgumentNullException("commandText")

        ' If the provided connection is not open, we will open it
        If connection.State <> ConnectionState.Open Then
            connection.Open()
            mustCloseConnection = True
        Else
            mustCloseConnection = False
        End If

        ' Associate the connection with the command
        command.Connection = connection

        ' Set the command text (stored procedure name or SQL statement)
        command.CommandText = commandText

        ' If we were provided a transaction, assign it.
        If Not (transaction Is Nothing) Then
            If transaction.Connection Is Nothing Then Throw New ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction")
            command.Transaction = transaction
        End If

        ' Set the command type
        command.CommandType = commandType

        ' Attach the command parameters if they are provided
        If Not (commandParameters Is Nothing) Then
            AttachParameters(command, commandParameters)
        End If
        Return
    End Sub     ' PrepareCommand

#End Region

#Region "ExecuteNonQuery"

    ' Execute a oledbCommand (that returns no resultset and takes no parameters) against the database specified in 
    ' the connection string. 
    ' e.g.:  
    '  Dim result As Integer =  ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders")
    ' Parameters:
    ' -connectionString - a valid connection string for a oledbconnection
    ' -commandType - the CommandType (stored procedure, text, etc.)
    ' -commandText - the stored procedure name or T-SQL command
    ' Returns: An int representing the number of rows affected by the command
    Public Overloads Shared Function ExecuteNonQuery(ByVal connectionString As String, _
      ByVal commandType As CommandType, _
      ByVal commandText As String) As Integer
        ' Pass through the call providing null for the set of oledbParameters
        Return ExecuteNonQuery(connectionString, commandType, commandText, CType(Nothing, oledbParameter()))
    End Function        ' ExecuteNonQuery

    ' Execute a oledbCommand (that returns no resultset) against the database specified in the connection string 
    ' using the provided parameters.
    ' e.g.:  
    ' Dim result As Integer = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new oledbParameter("@prodid", 24))
    ' Parameters:
    ' -connectionString - a valid connection string for a oledbconnection
    ' -commandType - the CommandType (stored procedure, text, etc.)
    ' -commandText - the stored procedure name or T-SQL command
    ' -commandParameters - an array of SqlParamters used to execute the command
    ' Returns: An int representing the number of rows affected by the command
    Public Overloads Shared Function ExecuteNonQuery(ByVal connectionString As String, _
      ByVal commandType As CommandType, _
      ByVal commandText As String, _
      ByVal ParamArray commandParameters() As oledbParameter) As Integer
        If (connectionString Is Nothing OrElse connectionString.Length = 0) Then Throw New ArgumentNullException("connectionString")
        ' Create & open a oledbconnection, and dispose of it after we are done
        Dim connection As oledbconnection = Nothing
        Try
            connection = New oledbconnection(connectionString)
            connection.Open()

            ' Call the overload that takes a connection in place of the connection string
            Return ExecuteNonQuery(connection, commandType, commandText, commandParameters)
        Finally
            If Not connection Is Nothing Then connection.Dispose()
        End Try
    End Function        ' ExecuteNonQuery

    ' Execute a stored procedure via a oledbCommand (that returns no resultset) against the database specified in 
    ' the connection string using the provided parameter values.  This method will discover the parameters for the 
    ' stored procedure, and assign the values based on parameter order.
    ' This method provides no access to output parameters or the stored procedure' s return value parameter.
    ' e.g.:  
    '  Dim result As Integer = ExecuteNonQuery(connString, "PublishOrders", 24, 36)
    ' Parameters:
    ' -connectionString - a valid connection string for a oledbconnection