Dim cat As New Catalog()
Dim con As New OleDbConnection()
Dim cmd As New OleDbCommand
Dim ds1 As New DataSet
Dim conn As ADODB.Connection
' Open the Access database.
conn = New Connection
conn.ConnectionString =
"Provider=Microsoft.Jet.OLEDB.4.0;" &
"Data Source=" + openExcel + "\Test" + ".mdb; Persist Security Info=False"
con.ConnectionString =
"Provider=Microsoft.Jet.OLEDB.4.0;" &
"Data Source=" + openExcel + "\Test" + ".mdb; Persist Security Info=False"
conn.Open()
xlWorkSheet1.Columns(5).Insert
Dim cellValue As String = ""
Dim newValue As String = ""
Dim sh1 As String = ""
Dim qty As String = ""
Dim matchText As String = ""
Dim sql As String = ""
con.Open()
sh1 = LTrim$(xlWorkSheet1.Cells(i, 1).Text)
sql = "SELECT Num_ber, Q_ty FROM good WHERE Na_me LIKE 'staff%' And Ty_pe = 'ORD'"
Dim cmd As New OleDbCommand(sql, con)
Dim myReader As OleDbDataReader = cmd.ExecuteReader()
conn.Execute(sql)
myReader = cmd.ExecuteReader() ' HERE'S THE PROBLEM
xlWorkSheet1.Cells(1, 5) = myReader.GetString(0)
xlWorkSheet1.Cells(1, 11) = myReader.GetString(1)
myReader.Close()
conn.Close()
conn = Nothing
**I wanted to retrieve a specific value from mdb and then write it to excel.
Here's my code, I got this error so many times and I can't find it out. Can anybody help me? Thanks.**
[1]: https://i.stack.imgur.com/6Fuvg.png
Ok, you first have to decide when usng .net what "provider" you are going to use, AND THEN decide what kind of data objects you want to use.
You can use a oracle provider, a sql server provider, or in this case, since we using Access, then we can use EITHER oleDB, or ODBC. Either choice is fine. Most use oleDB providers for Access, but often ODBC is a good choice, especially if down the road you plane to swap out Access for say SQL server.
What the above means in plain English?
You don't want to adopt the external ADODB code and library. That code is NOT .net, and thus you REALLY but REALLY do not want to write your .net code that way. ADODB was written LONG before .net, and is what we call un-managed code (non .net). I strong, but strong suggest you do NOT add a reference to ADODB to your project, and I beyond strong recommend you avoid introduction of a non .net library for doing this!!! We certainly can adopt the oleDB provider in .net, but we will NOT have a direct reference to JET/ACE (the access database engine) in our applcation. As noted, there are some exceptions to this suggesting, but they don't apply to you and here.
Next up:
The design pattern in .net is to create the connection, get the data, and CLOSE the connection. This "pattern" will then be 100% sure that the data base is always closed, and you NEVER have to worry about if the connection is open, closed, or even if you forgot to close the connection!!! So, do this correct, and some "open" connection will never bite you, or will you have to worry about this issue.
You can in some operations keep the connection open for performance, but lets learn to walk before we run so to speak.
next up:
We certainly do NOT want to place and have connection strings all over in our code. Not only is this going to wear out your keyboard, but if you ever need to change the connection, then you going to have to hunt down all that code.
Best to let Visual Studio save that connection in ONE location, and MORE important MANAGE this for you!!!
Next up:
Do you ONLY need to work with mdb files, or do you plan/need to work with accDB files? This is a HUGE issue, and one that you cannot ignore.
next up:
Are you going to use the x32 bit version of the Access database system, or the x64 bit version?
Since your example posted code uses JET (access data engine for mdb files ONLY x32 bit version)?
Then this ALSO means you MUST (and I repeat MUST) force your .net project to run as x32 bits. You cannot use "any cpu", and you cannot use x64 bits, you MUST choose x86 bit size for your .net project. Failure to do so will result in the project not working.
Ok, with the above information?
First up, force/set/be 100% sure your project is set to run as x32 bits.
That setting is this one:
and remove the reference you have to ADO if you created one.
Ok,
next up:
Create the connection to the database.
Project ->properties.
This here:
And then:
and then
Now, you can browse, and select the access mdb file.
But, you MUST not skip the next step - you have to choose JET (older, mdb files), or choose the newer ACE (for accDB format files).
So, this:
now this:
As noted, you choose JET or ACE here.
now, we have this and you can use test connection.
BUT BE VERY careful!!!!
If you are using vs2022, then keep in mind vs2022 is the FIRST version of VS that is now x64 bits. As a result, vs can't pass the test connection!!! Your connection is in fact ok, but will fail with vs2022.
If you using a previous version of VS (before 2022), then the test connection button should work. and you see this:
Ok, now that we have a valid working conneciton setup, we can now write code, and we will NOT use ADODB!!!!
The typical code pattern to read and load a data table (like a access VBA recordset) will be like this:
Now, I became RATHER tired of writing that same using block over and over. So, in a global module, I have this code now:
Public Function MyRst(strSQL As String) As DataTable
Dim rstData As New DataTable
Using conn As New OleDbConnection(My.Settings.AccessDB)
Using cmdSQL As New OleDbCommand(strSQL, conn)
conn.Open()
rstData.Load(cmdSQL.ExecuteReader)
End Using
End Using
Return rstData
End Function
So, now with the above handy dandy helper routine?
Your code becomes this:
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Dim Sql As String =
"SELECT Num_ber, Q_ty FROM good WHERE Na_me LIKE 'staff%' And Ty_pe = 'ORD'"
Dim rstData As DataTable = MyRst(Sql)
Debug.Print("Na_me is " & rstData.Rows(0).Item("Na_me"))
End Sub
Or, display all return rows from that data table
Debug.Print("Na_me is " & rstData.Rows(0).Item("Na_me"))
For Each OneRow As DataRow In rstData.Rows
Debug.Print("na_me = " & OneRow("Na_me"))
Next
So, you really don't need (or want) a reader anyway. Just load the results into a nice clean, easy to use data table, and from that you can loop the table, grab rows, or do whatever you want.
Rewriting a legacy system in VB 2013 Express which connects to an Access DB. I've set up the Data Connection and have a DataSet with all the tables. The code needs to do the following:
Delete all the rows in the "extract" table;
Read in and parse the new data;
Write the new data to the "extract" table.
I've got the reading and parsing part done, but I need help with the deleting and writing part. Nothing I try seems to work.
This is what i've tried:
Dim sqlConnection1 As New System.Data.SqlClient.SqlConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=|DataDirectory|\CLI_CRVM.accdb")
Dim cmd As New System.Data.SqlClient.SqlCommand()
cmd.CommandType = System.Data.CommandType.Text
cmd.CommandText = "DELETE FROM extract"
cmd.Connection = sqlConnection1
You are trying to use System.Data.SqlClient, but that is specifically for working with Microsoft SQL Server databases. The example code in your question will fail with
Keyword not supported: 'provider'.
For an OLEDB connection to your Access database, use System.Data.OleDb.
I'm using a SQL Server Compact database (3.5). I have run through every article on this site (and others) I could find about this issue, but can't seem to find the problem. I am using Visual Studio 2012, VB.Net.
My provider string is:
Dim sqlConn As New System.Data.OleDb.OleDbConnection("Provider=Microsoft.SQLServer.CE.OLEDB.3.5;Data Source=" & My.Application.Info.DirectoryPath & "\pw.sdf" & ";Password=XXXyyy1234;Persist Security Info=True;")
My code where it all breaks down is:
'Create SQL Query
Dim SQLString As String = "SELECT * FROM EmailGroups"
'Create Dataset, Open Connection
Dim dsPWC As New DataSet()
Dim OleDbDataAdapter1 As System.Data.OleDb.OleDbDataAdapter = New System.Data.OleDb.OleDbDataAdapter(SQLString, sqlConn)
sqlConn.Open()
And, of course, it breaks down on .Open().
I picked selecting from that datatable because it is a simple one.
EmailGroup_UID [int][PK]
EmailGroup_Name [nvarchar][length=50]
I'm sure I've been simply staring at this too long and can't see the forest for the trees anymore, so I'm hoping someone can slap me straight :)
Thanks in advance.
EDIT: This code all works when tying to the original MS Access 2007 database (accdb). Different provider, of course. And - I didn't import the tables, I re-created manually.
2nd EDIT: Immediate Window says 'A first chance exception of type 'System.Data.OleDb.OleDbException' occurred in System.Data.dll'
You should use SqlCeConnection instead of OldDbConnection.
if you must use OleDbConnection, use "ssce:database password" like so:
"Provider=Microsoft.SQLServer.CE.OLEDB.3.5;Data Source=" & My.Application.Info.DirectoryPath & "\pw.sdf" & ";SSCE:Database Password=XXXyyy1234;Persist Security Info=True;"
I've succesfully synchronized both source and local db using the local database cache item in VS 2008.
However, I need to access the SQL CE db directly from within another dll/process, and without using a dataset. The reason being that my business object code does not use datasets.
The final code wouldlook something like this:
Dim conn As New SqlServerCe.SqlCeConnection("Data Source=C:\Development\UserDirectory\UserDirectory.DBSyncher\ProfDir.sdf;Persist Security Info=False;")
Dim cmd As New SqlServerCe.SqlCeCommand("Select EmailAddress from Employees Where ID=23", conn)
Dim returnString As String = ""
If conn.State = ConnectionState.Closed Then
conn.Open()
End If
returnString = cmd.ExecuteScalar
conn.Close()
cmd = Nothing
I notice something very strange using a dataset the synchronized changes are shown but accessing the CE database file directly returns old data - no synched data whatsoever.
What am I missing? Any help would be greatly appreciated.
Figured it out!
Forgot that CE is in process, thus it copies the database file(.sdf) to the Debug folder. You have to to reference that database not the one in your project. DOH!
I've found a few examples of using vb.net to access an sql database, so far none of them have worked . They all involve using DataReaders. Maybe its the fact that the sql db is not on the same machine as the application.
I was just wondering if anyone had a more comprehensive example of using VB.NET to access a remote sql server.
Thanks!
EDIT:
I've received a few helpful comments an replies already. So far my connection string looks like:
"server=sqlblah.myhost.com;uid=myuser;pwd=pass;database=testdb"
Probably also good to mention their is no editing of the tables a this point, just reading.
Check out the SQLClient class.
One convienent way to access a SQL database is to fill a DataSet object with query data with a DataAdapter object.
Dim sSQL As String = "SELECT * FROM ???"
Dim conn As New SqlClient.SqlConnection("connection string")
Dim da As New SqlClient.DataAdapter(sSQL, conn)
Dim ds As New DataSet
da.Fill(ds, "TABLE NAME")
You can then access the "TABLE NAME" table in the DataSet object.
The "connection string" is obviously your SQL connection string.
Use the sSQL string to query as necessary.
Quick side note - a helpful tool for creating connection strings:-
Open up a text document (notepad, wordpad etc) and save a blank document with the extension ".UDL".
This will give you a "Data link Properties" mini app.
Open up the app and change the provider in the "Provider" to whichever provider you need (in this case OLE DB Provider for SQL Server).
You then need to build up the connection in the connection tab.
Once you have chosen the criteria (ServerName (the drop down list will show you all visible Servers), Security permissions,Database (this drop down list will be populated based on the server chosen)) you can test your connection (to make sure you have permissions etc).
Click ok to close the App, rename the file to have a ".txt" extension and re-open in a text editor, hey presto, one built up connection string (as below).
Provider=SQLOLEDB.1;Integrated Security=SSPI;Persist Security Info=False;Initial Catalog=YOURDBNAME;Data Source=YOURSERVERNAME