That's my first post here, so please indicate me if there are some missing useful informations' to help to solve my problem.
Here is it:
I have a VB.net application using Access database (.mdb), which worked properly for years.
Because I'm using now Access Database Engine 2016 in 64-bits, I have changed my DB connection provider from Microsoft.Jet.OLEDB.4.0 (only available in 32-bits) to Microsoft.ACE.OLEDB.12.0. I've also unchecked in my app's properties "32-bits prefered" (translation from my French version of Visual Studio).
Since I did these changes (and only them), I often get the following error:
System.AccessViolationException: 'Attempted to read or write
protected memory. This is often an indication that other memory is
corrupt.
It appears (randomly) in different parts of the software, always at the line myConnection.Open()
Dim myConnection As OleDbConnection = New OleDbConnection(S7ConnString)
Try
myConnection.Open()
...
First new connection string with which I began to get this problem is:
Public S7ConnString As String = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" & DBPath & ";Jet OLEDB:Database Password=***;"
(where DBPath is a string for the Access .mdb file path)
After some searches, I've read that adding OLE DB Services=-1 could solve it. It improved speed of DB processes really much, but did not solved the problem.
Would you have any idea to solve this?
Thank you & Kind regards.
I have uninstalled Access Database Engine 2016 and installed 2010 64-bits version, and it seems to work correctly now.
Thank you for your suggestions, #Jimi, that helped me to solve this. I did not imagine "Microsoft.ACE.OLEDB.12.0" provider was not compatible with MS Access Database Engine 2016!
Related
After switching from Office 365 32 bit to Office 64 bit the connection to Visual Foxpro does not work anymore.
So with :
"Provider=Advantage OLE DB Provider; Data Source=D:ACCESSImport; ServerType=ADS_LOCAL_SERVER; TableType=ADS_VFP;"
and
Dim AdsGetCustRecordset As ADODB.Recordset
Set AdsGetCustRecordset = New ADODB.Recordset
AdsGetCustRecordset.Open "SELECT * FROM TABLE", objcon, adOpenDynamic, adLockPessimistic, adCmdText
Actually the access is possible. However with error messages from the Advantage Client Engine.
"exception code was generated when calling the user supplied callbackfuntion . it is being disabled"
Maybe someone can help me.
Many thanks in advance
Advantage Database has both a 32- and 64-bit drivers, make sure you have correct version. If you are not seeing the
ACE64.dll
ADSLOC64.dll
ADSOLEDB64.dll
AICU64.dll
AXCWS64.dll
That is probably why.
We have this VB.net code that connects to an MS Access Database and tries to insert a new entry:
Dim conn As New OleDbConnection
conn.ConnectionString = "Provider="Microsoft.ACE.OLEDB.16.0; Data Source=" & DATABASE_PATH & ";Jet OLEDB:Database Password=pass;"
conn.Open()
Dim SqlString As String = "INSERT INTO tblNotes" &
" ([NotesNumber" &
"], [NotesTitle" &
"], [HasAdditionalLogic" &
"], [TypeId]) Values (?,?,?,?)"
Dim cmd As New OleDbCommand(SqlString, conn)
cmd.CommandType = CommandType.Text
cmd.Parameters.AddWithValue("NotesNumber", 1234)
cmd.Parameters.AddWithValue("NotesTitle", "the title")
cmd.Parameters.AddWithValue("HasAdditionalLogic", False)
cmd.Parameters.AddWithValue("TypeId", 14)
cmd.ExecuteNonQuery()
conn.close()
Nothing too fancy, right?
This code worked fine with Access 2016 installed.
Now with the recent upgrade to Office 365 the line
cmd.ExecuteNonQuery()
causes this error:
'Microsoft.ACE.OLEDB.16.0' failed with no error message available, result code: E_OUTOFMEMORY(0x8007000E)
Googling for that error message lead to several ideas like using Integer instead of Long Integer in the database, but that did not help either.
And personally, I doubt that the root cause is a lack of memory because the machine has 32GB RAM installed and is set to 32GB of Virtual Memory. The process itself never uses more than 100MB, Windows Process Explorer tells us that the whole RAM uses about 5GB total. So I just cannot believe we are actually running out of memory here.
Any idea?
Update:
Okay, we seem to have found the underlying issue here.
You see this line:
cmd.Parameters.AddWithValue("TypeId", 14)
In the Access database, the field "TypeId" has been defined as a Primary Key of Data Type "AutoNumber" and Field Size "Long Integer".
Now, if we write the code like this:
cmd.Parameters.AddWithValue("TypeId", 14I)
it runs without an error, but as soon as we change it to:
cmd.Parameters.AddWithValue("TypeId", 14L)
we get the crash.
Let me state again that the code with a Long works fine with Access 2016, it crashes with the Access from Office 365.
I may be mistaken, but this seems like a bug in Access.
Of course we can now change all the app code from Long to Integer (or UInteger), but this seems like treating the symptoms instead of the root cause.
Can somebody confirm this? Or tell me why exactly this happens? Using a Long seems to be correct to me, using an Integer instead seems pretty wrong to me.
To anybody who might face the same problem: we "fixed" the issue by installing "Microsoft Access Database Engine 2010 Redistributable"
https://www.microsoft.com/en-US/download/details.aspx?id=13255
and then using
Microsoft.ACE.OLEDB.12.0
instead of
Microsoft.ACE.OLEDB.16.0
That did the trick.
The hint with .add instead of .addWithValue did not make any difference.
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'm having trouble with my vb.net program. It has a database with a SqlConnection string of:
DbConn = New SqlConnection("Data Source=ACE-DUO;Initial Catalog=db_CVSO;Persist Security Info=True;User ID=sa;Password=pwd")
I made an installer for this vb.net program but I'm having problems regarding my SQL Server connection string. It's because once I installed the program in different computer. The server name in my case (ACE-DUO) changes and the database itself cannot be located.
I know how to detach the file and attach it to vb.net program. what I'm really aiming for is that I want the connection string to change on based where the program resources were placed.
For example, if the program was installed in the C:\Program Files\MyDatabase folder, I want to make it as a part of the connection string so it would be opened in different computer.
If you don't need multiple shared access to your database you could take advandage of the LocalDB feature of Sql Server 2012.
You connection string could be changed to
DbConn = New SqlConnection("Server=(localdb)\v11.0;Integrated " & _
"Security=true;AttachDbFileName=C:\Program Files\MyDatabase\db.mdf;"
Article on LocalDB
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