[Resolvido] Diferentes conexões e consultas, qual a melhor?

[tiagoborges.net 0]

Qual a diferença entre esta conexão e consulta:

 

Dim vConexao
 Set vConexao = Server.CreateObject("ADODB.Connection")
  vConexao.Open "DBQ="& request.ServerVariables("APPL_PHYSICAL_PATH") &"..\banco\baseSqltbNET.mdb;Driver={Driver do Microsoft Access (*.mdb)};"
   Set vRs = Server.CreateObject("ADODB.Recordset")
	vRs.Open "SELECT * FROM tbContador",vConexao,3,3
	 vRs.AddNew
	  vRs("txIp") = Request.ServerVariables("REMOTE_ADDR")
	  vRs("dhAcesso") = now
	 vRs.UpDate
	 vRs.MoveLast
	 Response.Write("	 Acessos: <b>"& vRs("idContador") &"</b> | "& vbcrlf)
	vRs.Close
   Set vRs = Nothing
  vConexao.Close
 Set vConexao = Nothing

Para outra que usa .Open() e Execute() Select, Insert, Update?

 

Em qual das duas eu ganho maior performance? Outra coisa, é errado o modo da primeira?

 

Como, fazer no primeiro modo em Asp.NET (VB)?

[roberto182 0]

Bom Dia,

 

Então amigo, este primeiro modo que você descreveu tem um problema de ser um late binding. Neste caso, você poderia só encontrar erros em tempo de execução. O que não seria interessante.

 

No .net temos alternativas bem mais interessantes, com early binding e que ainda possibilitam a criação e objeto de acesso a dados fortemente tipados.

 

Se você deseja apenas uma simples consulta use o data reader

http://64.233.169.104/search?q=cache:IXYyo...lient=firefox-a

 

Se você vai fazer diversas operações com essa tabela, então vá de dataset: http://www.asp.net/learn/data-access/tutorial-01-vb.aspx

 

Performaticamente, o datareader é muito superior, mas não é fortemente tipado, é somente leitura para frente e trabalha de maneira conectada. Se nada disso for um problema... então... é datareader.

 

Abraço

[tiagoborges.net 0]

Mas nao entendi como fazer a ligacao ao MDB

[roberto182 0]

Basta definir sua connection string e usar o OleDb ao invés do Sql

 

Ex.:

 

CODE

Dim sConnectionString, sSQL As String

 

'SQL Connection String

sConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=c:\yourdatabase.mdb"

 

sSQL = "SELECT Title FROM yourTable"

 

Dim conn As New System.Data.OleDb.OleDbConnection(sConnectionString)

Dim cmd As New System.Data.OleDb.OleDbCommand(sSQL, conn)

Dim dr As System.Data.OleDb.OleDbDataReader

conn.Open()

 

dr = cmd.ExecuteReader()

 

Do While dr.Read()

System.Console.WriteLine(dr.Item("Title"))

Loop

 

dr.Close()

conn.Close()

[tiagoborges.net 0]

Isso me ajudou:

 

Option Explicit

   Private Sub cmdOpen_Click()
	   Dim Conn1 As New adodb.Connection
	   Dim Cmd1 As New adodb.Command
	   Dim Errs1 As Errors
	   Dim Rs1 As New adodb.Recordset

	   Dim i As Integer
	   Dim AccessConnect As String

	   ' Error Handling Variables
	   Dim errLoop As Error
	   Dim strTmp As String

	   AccessConnect = "Driver={Microsoft Access Driver (*.mdb)};" & _
					 "Dbq=nwind.mdb;" & _
					 "DefaultDir=C:\program files\devstudio\vb;" & _
					 "Uid=Admin;Pwd=;"

	   '---------------------------
	   ' Connection Object Methods
	   '---------------------------

	   On Error GoTo AdoError  ' Full Error Handling which traverses
							   ' Connection object

	   ' Connection Open method #1:  Open via ConnectionString Property
	   Conn1.ConnectionString = AccessConnect
	   Conn1.Open
	   Conn1.Close
	   Conn1.ConnectionString = ""

	   ' Connection Open method #2:  Open("[ODBC Connect String]","","")
	   Conn1.Open AccessConnect
	   Conn1.Close

	   ' Connection Open method #3:  Open("DSN","Uid","Pwd")
	   Conn1.Open "Driver={Microsoft Access Driver (*.mdb)};" & _
				  "DBQ=nwind.mdb;" & _
				  "DefaultDir=C:\program files\devstudio\vb;" & _
				  "Uid=Admin;Pwd=;"
	   Conn1.Close


	   '--------------------------
	   ' Recordset Object Methods
	   '--------------------------

	   ' Don't assume that we have a connection object.
	   On Error GoTo AdoErrorLite

	   ' Recordset Open Method #1:  Open via Connection.Execute(...)
	   Conn1.Open AccessConnect
	   Set Rs1 = Conn1.Execute("SELECT * FROM Employees")
	   Rs1.Close
	   Conn1.Close

	   ' Recordset Open Method #2:  Open via Command.Execute(...)
	   Conn1.ConnectionString = AccessConnect
	   Conn1.Open
	   Cmd1.ActiveConnection = Conn1
	   Cmd1.CommandText = "SELECT * FROM Employees"
	   Set Rs1 = Cmd1.Execute
	   Rs1.Close
	   Conn1.Close
	   Conn1.ConnectionString = ""

	   ' Recordset Open Method #3:  Open via Command.Execute(...)
	   Conn1.ConnectionString = AccessConnect
	   Conn1.Open
	   Cmd1.ActiveConnection = Conn1
	   Cmd1.CommandText = "SELECT * FROM Employees"
	   Rs1.Open Cmd1
	   Rs1.Close
	   Conn1.Close
	   Conn1.ConnectionString = ""

	   ' Recordset Open Method #4:  Open w/o Connection & w/Connect String
	   Rs1.Open "SELECT * FROM Employees", AccessConnect, adOpenForwardOnly
	   Rs1.Close

   Done:
	   Set Rs1 = Nothing

	   Set Cmd1 = Nothing
	   Set Conn1 = Nothing

	   Exit Sub


   AdoError:
	   i = 1
	   On Error Resume Next

	   ' Enumerate Errors collection and display properties of
	   ' each Error object (if Errors Collection is filled out)
	   Set Errs1 = Conn1.Errors
	   For Each errLoop In Errs1
		With errLoop
		   strTmp = strTmp & vbCrLf & "ADO Error # " & i & ":"
		   strTmp = strTmp & vbCrLf & "   ADO Error   # " & .Number
		   strTmp = strTmp & vbCrLf & "   Description   " & .Description
		   strTmp = strTmp & vbCrLf & "   Source		" & .Source
		   i = i + 1
		End With
	   Next

   AdoErrorLite:
	   ' Get VB Error Object's information
	   strTmp = strTmp & vbCrLf & "VB Error # " & Str(Err.Number)
	   strTmp = strTmp & vbCrLf & "   Generated by " & Err.Source
	   strTmp = strTmp & vbCrLf & "   Description  " & Err.Description

	   MsgBox strTmp

	   ' Clean up gracefully without risking infinite loop in error handler
	   On Error GoTo 0
	   GoTo Done
   End Sub

http://support.microsoft.com/kb/168336/pt-br