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;"
Related
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.
So I'm using this post as a last resort, newcomer here, my connection string currently looks like this for my local MSSQL database:
Dim Conn As New SqlConnection("Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=C:\Users\steve\OneDrive\Desktop\UNIT 5 CS\MonmouthCanoeAndActivityCentre\MonmouthCanoeAndActivityCentre\.vs\MonmouthCanoeAndActivityCentre\.vs\MonmouthCanoeAndActivityCentre\v16\WorkerLogin.mdf;Integrated Security=True;Connect Timeout=30")
which is of course incredibly clunky and also hard coded to my personal laptop. My problem is that I want to be able to run the connection on any new device I send the project to without them having to change the directory of the connection string themselves.
Any advice would be helpful, I'm not incredible at visual basic either so sorry if I question.
Answering my own question to hopefully help some poor future soul.
the new connection string is:
Dim conn As New SqlConnection("Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=" & Application.StartupPath & "InsertFileNameHere.mdf;Integrated Security=True;Connect Timeout=30")
The .mdf file of your database has to be in the same place as your Application.StartupPath but you can find this with a simple:
Dim location As String = Application.StartupPath
MessageBox.Show(location)
and a test button to activate the above ^
I have been searching for a couple hours, and found several questions, but none of them really explained this in a way I can understand.
I'm programming a game similar to Rock Paper Sissors, except with many more selections, and the possiblity of a tie. I had originally hardcoded all of the possible outcomes, then decided to try a database so I can learn and practice sql as well.
Problem is, I can't figure out for the life of me how to connect to my local database, now that I have set it up and filled it through Visual Studio 2010. I can connect to it through Server Explorer just fine, and I can see it in Solution Explorer. I've tried several things, along the lines of:
Private sqlConn As New SqlConnection("Data Source=(local)|DataDirectory|\Outcomes.sdf;database=Outcomes;Integrated Security=true")
Private sqlConn As New SqlConnection("Data Source=.\SQLEXPRESS; Integrated Security=true")
Dim sqlConn As SqlConnection
sqlConn = New SqlConnection("DataSource=..\..\Outcomes.sdf")
I am relatively new to sql, but know enough through tinkering to build a sql statement and get me the result I want. But I've never connected to a database before. I've looked on MSDN and tried several things I saw on there (everything that looked like what I needed, really) but it still hasn't worked.
If I can connect, I already have my statement set, and have tested it through the database itself. Any help would be wonderful, especially if it's explained in a way I can understand it and use it for later.
Also, if it helps and isn't noticed through my tried code, my db name is Outcomes. I don't know if that is needed or will help, but just in case.
Please visit connection strings here...
It also would have been helpful to know what type of DBMS you are using as well. I noticed you have an .sdf database file, not a DBMS (For ex: MySql, SQL or Oracle). Therefore, your connection string is really going to depend on what you want.
Your issue is here by the way...
Private sqlConn As New SqlConnection("Data Source=(local)|DataDirectory|\Outcomes.sdf;database=Outcomes;Integrated Security=true")
*You cant use the SqlConnection you have because its not supported with the use of .sdf files.
Instead you have to use: System.Data.SqlServerCe 'This is for compact edition
If you would like to know more about this please see here.
Kendra,
Here are the logical Steps you will need to follow to access the database programmatically:
Note: I'm assumming you have the proper SQLExpress | SQL Server Database setup whether local or remote the methods below are identical except for the connection string information.
1) Import the Sql AdoNet Namespace so you can use the proper SQL Server Client Objects & Methods;
a) Imports System.Data.SqlClient
2) Establish a Connection to the database with the ADO Connection Object:
' Create your ADO Connection Object:
Private myConn As SqlConnection
myConn = New SqlConnection("Initial Catalog=OutComes;" & _
"Data Source=localhost;Integrated Security=SSPI;")
Note: This connection string uses integrated security from your windows machine. you could also use standard security where you would need to enter your username and password credentials. Its your choice.
3) Setup Your ADO Command Object to Define your data retrieval query:
'Create a Command object.
Private myCmd As SqlCommand
myCmd = myConn.CreateCommand
myCmd.CommandText = "SELECT FirstName, LastName FROM Employees"
'Open the connection.
myConn.Open()
Note: Subsitute CommandText string for your actual query based upon your own database schema.
4) Read, Fetch, Display Data using the SQLDataReader Object:
Private results As String
Private myReader As SqlDataReader
myReader = myCmd.ExecuteReader()
'Traverse the DataSet and Display in GUi for Example:
Do While myReader.Read()
results = results & myReader.GetString(0) & vbTab & _
myReader.GetString(1) & vbLf
Loop
'Display results.
MsgBox(results)
5) Gracefully Close all Objects Used:
' Close the reader and the database connection.
myReader.Close()
myConn.Close()
Note - You'll need to consult microsoft for further connection string formats, since I don't have enough info. But this should clarify the actual big picture steps for you.
Regards,
Scott
I have inherited software to maintain. The previous version used a third party Datagridview substitute that isn't compatible with versions of Windows from Vista on. In attempting to put Datagridviews in I have run into a problem with connecting to the database.
I am trying to make a small program to play around with connection and SELECT outside of the original software so I can further understand what I am doing and without going through the full process of using the original software to get to the testing point.
Private Shared Function GetData(ByVal sqlCommand As String) As DataTable
Dim table As New DataTable()
Dim connectionString As String = "Data Source=.\SQLExpress;Integrated Security=true;" _
& "AttachDbFilename=C:blah\blah\blah.mdf;User Instance=true;"
Using con = New SqlConnection(connectionString)
Using command = New SqlCommand(sqlCommand, con)
Using da = New SqlDataAdapter(command)
da.Fill(table)
End Using
End Using
End Using
Return table
End Function
My SQL command is a simple "Select * FROM Setup" and the rest of the program is form loads, imports, and DataGridView formatting. I don't think it affects the SQL part and would be cumbersome to include here.
This results in what appears to be a closed connection.
![Connection Property] http://i.imgur.com/b5V3Qy5.png
This is a screenshot of my SQLExpress which might help diagnose connection problems.
![SQL Properties] http://i.imgur.com/bakBq5D.png
I've blurred out the computer name in grey, but I did notice that there was another computer name in pink. I don't know what it means other than maybe this database was originally created on another computer and has been copied and pasted.
Finally this is the connection string that the original software used:
"Data Source=.\SQLExpress;AttachDbFilename=C:\blah\blah\blah.mdf;Trust_Connection=Yes;"
I have also tried:
"Data Source=.\SQLExpress;AttachDbFilename=C:\blah\blah\blah.mdf;Trusted_Connection=Yes;User Instance=true"
Finally, this is my exception:
"An attempt to attach an auto-named database for file C:\blah\blah\blah.mdf failed. A database with the same name exists, or specified file cannot be opened, or it is located on UNC share."
I got my alternate connection strings from www.connectionstrings.com.
You are missing the Open() command.
con.Open()
Full code listing. (Also a good idea is to wrap your code in a Try.... End Try block).
Private Shared Function GetData(ByVal sqlCommand As String) As DataTable
Dim table As New DataTable()
Dim connectionString As String = "Data Source=.\SQLExpress;Integrated Security=true;" _
& "AttachDbFilename=C:blah\blah\blah.mdf;User Instance=true;"
Using con = New SqlConnection(connectionString)
conn.Open()
Using command = New SqlCommand(sqlCommand, con)
Using da = New SqlDataAdapter(command)
da.Fill(table)
End Using
End Using
End Using
Return table
End Function
I am fairly new to asp.net but have knowledge is vb. I am building an web application in visual studio 2012 using vb. I have a drop down list that is populated with two 2008 SQL Servers. There is another dropdown that will need to populated with a list of available databases on the selected server. I have a button that once clicked and the server is selected it will do a query and pull the list of databases
I have specified the server name in a globalvariables class and then imported it into the form I am using.
I am thinking that will need to do a IF statement that will need to say, If server1 is selected the open a connection and perform a query on the databases.
Here is my code that I have but its throwing an overload resolution failed because no accesible 'Open' accepts this number of arguments error:
Protected Sub getdb_Click(sender As Object, e As EventArgs) Handles getdb.Click
Dim objConnection As OleDbConnection
objConnection = CreateObject("OleDbConnection")
If DropDownList1.Text = globalvariables.servername1 Then
objConnection.Open("Provider=SQLOLEDB; Data Source=" & "globalvariables.servername1" & ";" & _
"Trusted_Connection=Yes; Initial Catalog=master")
End If
Please help me in getting the correct code as I have tried a number of items off of this site and nothing seems to work.
You use the New keyword to instantiate your objects
Dim serverName = DropDownList1.Text
Dim connectionString = "Provider=SQLOLEDB; Data Source=" & serverName & ";" & _
"Trusted_Connection=Yes; Initial Catalog=master"
Dim objConnection = new OleDbConnection(connectionString)
objConnection.Open()
and pass the instructions on how to open the database using a connectionString.
However, because you are using a SqlServer database why don't you use the specific classes provided for Sql Server?
SqlConnection, SqlCommand, SqlDataAdapter and so on....