con = New OleDb.OleDbConnection(Con_String)
cmd = New OleDb.OleDbCommand("delete from Accessed_DB where pathofdb =#pathofdb", con)
con.Open()
cmd.Parameters.RemoveAt("#pathofdb")
cmd.ExecuteNonQuery()
MsgBox("Record Deleted")
con.Close()
I am using above code to delete data but it not get successful. why?
cmd.Parameters.RemoveAt("#pathofdb")
should probably be
cmd.Parameters.AddWithValue("#pathofdb", "some path")
Having said that I don't think OLEDB supports named arguments in the SQL syntax so I think your command should be:
cmd = New OleDb.OleDbCommand("delete from Accessed_DB where pathofdb =?", con)
Related
I am new to the vb and I want to create project where if I click this button, form 2 will show and the information from it will change depends on what room button I click. i know how to connect a database but I am so clueless on how to make it that way, please help me. Thank you everyone
Dim con As New OleDb.OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\Users\arima\Documents\Consumer & rooms Database.mdb")
Yup, Stuck
You also need an OleDbCommand associated with the connection. The OleDbCommand.CommandText property is where your SQL statements go. Then you can .Open() the connection, so the command object can execute the SQL statements.
Here's the general idea:
Using con As New OleDbConnection("connection string here"), _
cmd As New OleDbCommand("SELECT * FROM MyTable WHERE MyColumn = ?", con)
cmd.Parameters.Add("?", OleDbType.VarWChar, 25).Value = "SomeValue"
con.Open()
Using rdr As OleDbDataReader = cmd.ExecuteReader()
While rdr.Read()
' Do something with each record
End While
End Using
End Using
Alternatively, you can use an OleDbDataAdapter to fill a DataTable or DataSet:
Dim dt As New DataTable
Using con As New OleDbConnection("connection string here"), _
da As New OleDbDataAdapter("SELECT * FROM MyTable WHERE MyColumn = ?", con)
da.SelectCommand.Parameters.Add("?", OleDbType.VarWChar, 25).Value = "SomeValue"
da.Fill(dt)
End Using
I want to Insert 2 different data in 2 different table of ms-access.
And it shows this error.
I have a code like this:
try
dim sql1,sql2 as string
sql1 = "INSERT INTO table1(something)VALUES(something)"
cmd = new oledbcommand(sql1, connection)
cmd.executenoquery()
sql2 = "INSERT INTO table2(something)VALUES(something)"
cmd2 = new oledbcommand(sql2, connection)
cmd2.executenoquery()
catch ex as exception
msgbox(ex.tostring())
(where these cmd1,cmd2 are defined in controlModule.)
so,what should I do ?
Any help is appreciated. Thank You
I think closing the connection fixes the issue, best by using the Using-statement:
try
Using con As OleDbConnection = GetConnection() ' or New OlebConnection(...)
Using cmd = con.CreateCommand()
cmd.CommandText = "INSERT INTO table1(something)VALUES(#something)"
cmd.Parameters.AddWithValue("#something", something)
con.Open()
cmd.ExecuteNonQuery()
End Using
End Using
Using con As OleDbConnection = GetConnection()
Using cmd = con.CreateCommand()
cmd.CommandText = "INSERT INTO table2(something)VALUES(#something)"
cmd.Parameters.AddWithValue("#something", something)
con.Open()
cmd.ExecuteNonQuery()
End Using
End Using
Catch ex As Exception
msgbox(ex.tostring())
End Try
This is a concurrency issue. Because some other part of your code or MS Access itself accesses the database at the same time.
The fact is that you're not closing the connection after it's use. So the 2nd call should fail with that exception. Instead, you should wrap your disposables - e.g. the OleDbConnection, commands, etc. - in a using statement. That way, the connection will be closed, even if an exception occur:
Using con As New OleDbConnection, cmd1 As OleDbCommand = con.CreateCommand, cmd2 As OleDbCommand = con.CreateCommand()
cmd1.CommandText = "INSERT INTO table1(something)VALUES(something)"
cmd1.ExecuteNonQuery()
cmd2.CommandText = "INSERT INTO table2(something)VALUES(something)"
cmd2.ExecuteNonQuery()
End Using
I have a devexpress gridview that is related to a table in a sql server database. I am trying to refresh the gridview right after performing a delete but nothing I've tried so far has worked. (I've verified that the delete operation has worked in the table). I've tried 3 ways of updating the gridview but nothing has worked:
GridControl1.Refresh()
GridView1.RefreshData()
GridControl1.RefreshDataSource()
GridView1.RefreshEditor(True)
Here is the complete code of the whole operation:
Using cnn As New SqlConnection(FrmGeneralConfig.GetInstance.getConnection())
Try
cnn.Open()
Dim daDelete As New SqlDataAdapter
Dim command As SqlCommand = New SqlCommand("DELETE FROM Client_Excepte_Charge_Min WHERE ClientNo = #ClientNo", cnn)
command.Parameters.AddWithValue("#ClientNo", clientNo)
daDelete.DeleteCommand = command
daDelete.DeleteCommand.ExecuteNonQuery()
cnn.Close()
Catch ex As Exception
MessageBox.Show("Erreur: " & ex.Message)
Finally
GridControl1.Refresh()
GridView1.RefreshData()
GridView1.RefreshEditor(True)
End Try
End Using
You need to update your DataTable after deleting the rows in server.
Here is example:
Using cnn As New SqlConnection(FrmGeneralConfig.GetInstance.getConnection())
Try
cnn.Open()
Dim command As SqlCommand = New SqlCommand("DELETE FROM Client_Excepte_Charge_Min WHERE ClientNo = #ClientNo", cnn)
command.Parameters.AddWithValue("#ClientNo", clientNo)
command.ExecuteNonQuery()
dtExceptions.Clear()
Using adapter As New SqlDataAdapter()
Dim selectCommand = New SqlCommand("SELECT * FROM Client_Excepte_Charge_Min", cnn)
adapter.SelectCommand = selectCommand
adapter.Fill(dtExceptions)
End Using
cnn.Close()
Catch ex As Exception
MessageBox.Show("Erreur: " & ex.Message)
End Try
End Using
the below code runs without error, but the MS Access table isn't updating. What am I missing?
Try
cnn = New OleDbConnection(ConfigurationManager.ConnectionStrings("accConnectionString").ToString())
cnn.Open()
Catch ex As Exception
Debug.Print("Oops - no connection to database")
Exit Sub
End Try
Dim sql As String
sql = "SELECT * FROM tblSend WHERE UploadedSuccessfullyOn is null ORDER BY QueuedOn;"
Dim da As New OleDbDataAdapter(sql, cnn)
Dim ds As New DataSet
da.Fill(ds, "dsQueuedToSend")
For Each dr As DataRow In ds.Tables("dsQueuedToSend").Rows
' Perform other unrelated tasks in this space, removed for brevity
' If those other tasks were successful, update Access.
If success = True Then
sql = "UPDATE [tblSend] SET [UploadedSuccessfullyOn] = #uploadedOn WHERE (([UploadID]) = #uploadId);"
Dim cmd As OleDbCommand
cmd = New OleDbCommand(sql, cnn)
cmd.Parameters.Add("#uploadedOn", OleDbType.Date).Value = Now
cmd.Parameters.Add("#uploadedId", OleDbType.Integer).Value = dr("UploadID")
cmd.ExecuteNonQuery()
cmd.Dispose()
Console.WriteLine("Success: updated.")
Else
Console.WriteLine("Failed: Not updated.")
End If
Next
da.Dispose()
cnn.Close()
I've also tried with:
sql = "UPDATE [tblSend] SET [UploadedSuccessfullyOn] = ? WHERE (([UploadID]) = ?);"
Or simply add the values in the not-preferred/non-parameter approach:
sql = "UPDATE [tblSend] SET [UploadedSuccessfullyOn] = #" & Now & "# WHERE (([UploadID]) = " & dr("UploadID") & ");"
Dim cmd As OleDbCommand
cmd = New OleDbCommand(sql, cnn)
cmd.ExecuteNonQuery()
cmd.Dispose()
None of these approaches updates the MS Access table. Ideas? Thanks!
One thing I have been caught by before with Visual Studio is that when embedding an Access database in a WinForms project, when you run the project, the Access database is copied over from the original to the runtime directory, overwriting any changes you've made.
This can create the illusion that an update is not taking place, when in fact if you check at the right moment, it is.
As you can probably very soon see, I am a complete newbie at VB.NET, and I am having some trouble getting output from a stored procedure in SQL Server 2005.
This is the code I use
Dim con As New SqlConnection
Dim cmd As New SqlCommand("esp_getDates", con)
Dim par As New SqlParameter("#PlaceID", SqlDbType.Int, 3906)
con.ConnectionString = "Data Source=localhost\SQLEXPRESS;Initial Catalog=ProgramDB;User ID=test;Password=test"
con.Open()
cmd.CommandType = CommandType.StoredProcedure
cmd.Parameters("#PlaceID").Direction = ParameterDirection.Output
cmd.ExecuteNonQuery()
con.Close()
I get the error;
An SqlParameter with ParameterName
'#PlaceID' is not contained by this
SqlParameterCollection.
Does anyone see what I'm doing wrong / have any suggestions how I can fix it? Code examples would be very helpful and any help is much appreciated.
You aren't actually adding the parameter to the cmd.Parameters collection:
cmd.Parameters.Add(par)
Alternatively, just add the parameter without instantiating the Parameter object explicitly:
cmd.Parameters.Add("#PlaceID", SqlDbType.Int)
cmd.Parameters("#PlaceID").Value = 3906
Also, I'd follow the principle of using a variable as close to the declaration as possible and reorganize things this way:
Dim con As New SqlConnection("Data Source=localhost\SQLEXPRESS;Initial Catalog=ProgramDB;User ID=test;Password=test")
con.Open()
Dim cmd As New SqlCommand("esp_getDates", con)
Try
cmd.CommandType = CommandType.StoredProcedure
cmd.Parameters.Add("#PlaceID", SqlDbType.Int)
cmd.Parameters("#PlaceID").Value = 3906
cmd.ExecuteNonQuery()
Finally
If cmd IsNot Nothing Then cmd.Dispose()
If cn IsNot Nothing AndAlso cn.State <> ConnectionState.Closed Then cn.Close()
End Try