I have a connection string in my app.config:
Code:
connectionString="data source=.sql2008 ;Database=Database1; Integrated Security=FALSE; Persist Security Info=True;" />
How do I change to another database (one of many) without using multiple strings? Can I change while the connection is open?
Code:
Dim myConn As New SqlConnection(System.Configuration.ConfigurationManager.AppSettings("ConnectionString"))
In our application we use IDataReader which actually call function from one.dll where weExecureDataReader()
We have many calls in application and in some places For some reason I am getting error message "DataReader already open" but I am not sure where.What will happend if I simple close that conection in the that .dll? Am I going to make trouble to database because one datareader left opened? I assume closing connection will close reader too and gargage collector will manage that left opened datareader..
SQL connections confuse me sometimes In almost every SQL related code on the internet the routine is like this;
* Open connection
* Execute SQL command
* Close connection
Is it good practice to just open a connection when the application starts and use that connection until the application closes?I know that sequential connections are required when processing more queries, but what if I need to poll a certain Table every x seconds? Isn't is better to keep that single connection open for as long as the application is running (and re-open when a failure occurs) instead of opening a new connection every x seconds?
If I use the CmdObj.ExecuteNonQuery() I got an error
I'm not having an open connectoin.
I have a VS 2008 .NET application which connects to many tables within a SQL 2005 database in order to fill controls using multiple DataSets and TableAdapters.how to appropriately change the database connection within my Visual Studio .NET 2008 application in a manner that will provent having to modify the datasets and tableadapters. Will changing the connectionstring shown in the DataSet/TableAdapters properties render them unusable?The tables within the production database are identical to the tables in the development database.
View 5 RepliesI have a problem with the connection to my database. It's on a remote server, and this is my code:
[Code]....
I have just written an application for myself and a few other users to use .rdp to connect to a number of servers, by clicking on the appropriate button. In the full version of the program I have two sets of connections one for when we are inside our vpn, which uses local ip addresses and DNS names; and the other which uses the external IP addresses and DNS names.This works quite well; if the user has stored credentials on their pc for the connection they connect straightaway; and if they don't the .rdp dialogue opens up with the server name/address filled in, ready for them to edit the rest of the required information.The problem for me is that this means I have to code 43 different Private Subs and then link the buttons; and I was hoping that instead of individually coding each connection, I could get the users to:Select by an option button whether the connection was internal or external
View 3 RepliesI am new to Visual basic and am using visual basic 2008 to write programs in, I have setup a database connection and the connection string is currently stored in the settings section of the project.I would like to have a menu item where when the user selects "test database connection" it will run the sub for testing if the database is established.
View 2 RepliesI need my program to connect to a database within my application i.e.What I have:
m_cnADONetConnection.ConnectionString = "Provider=Microsoft.jet.OLEDB.4.0;Data Source = C:Documents and SettingsmeroneyfMy DocumentsVisual Studio 2008ProjectsAsset Manager 2008inDebugDatabaseAssetManager.mdb"
What I need is: m_cnADONetConnection.ConnectionString = "Provider=Microsoft.jet.OLEDB.4.0;Data Source = DatabaseAssetManager.mdb"
I have used:System.Windows.Forms.Application.StartupPath & "ImagesSystemDefaultImage.bmp"
for loading of images within the default directory. but this returns the app path but also includes "System.Windows.Forms.Application.StartupPath" in the string?
1.Establishing a connection to a database(preferably one that is inherit within the project and can travel with it)
2. Setting the correct references to the database ( I tried connecting via JET with windows 7 and I get an error that I cannot use JET)
3. Query the database (Access) with SQL, and return those results to a recordset.
4. Loop through the recordset.
5. close the database connection
6. Open recordset and write data to table.
[Code]...
I've created a small DLL, an addin for Autodesk Inventor, this addin saves some information provided by the user and the program to an access(mdb)database.The whole idea behind this is that it allows users to quickly find drawings, assemblies and so on.The DLL works great on x86 systems however it has issues on x64 because I used ado.net.In a attempt to solve it I forced .net to compile it with the target x86 CPU settings.
However using this I'm unable register the dll (C:WINDOWSMicrosoft.NETFramework64v2.0.50727RegAsm.exe /codebase SavetoDatabase.dll )It says its not a proper .net dll file and therefore cannot be registered.
is there any other access-database connection provider (like dao or ado.net) that works on a 64 bit machine? Or do I need to change from mdb databases to another type (like mysql)? because sooner or later all machines its running on will be converted to x64.Or do I need to register the dll in another way?I've also tried to replace the conn.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0 with ACE, with no luck however
I have a .mdf file that I open through an Open Dialog Box and use in a ConnectionStringBuilder (where I have the user instance set to True). Later, in one of my button clicks, I try to open the connection (connection.Open()). It then gives me an error as follows: "Generating user instances in SQL Server is disabled. Use sp_configure 'user instances enabled' to generate user instances."
Here is my code:
Option Strict On
Imports System.Data.SqlClient
Public Class frmMain
[code]....
I am currently working on a login page using vb.net. I would like to know how to make connection to an access database and verify that the user logged in is a valid user
View 6 Repliesi want to know how to open a connection to database from vb.net
View 3 Repliesi am doin project using vb.net 2005 and using this sql query for connection
sql = "select username from login order by username"
con.ConnectionString = "Data Source=" & hostname & "; Initial Catalog=college;integrated security=sspi"
but m getting the following error:
Cannot open database "college" requested by the login. The login failed.Login failed for user 'CI4Admin'.
I am developing an application that is using a Jet database (Access 2007). The database is local to the project (e.g., on the same drive and in the project directory). Any time I attempt to access the database (to create another DataSet, etc., via designer, etc.), I get the ubiquitous "Failed to open a connection to the database" with:
No error message available, result code: E_UNEXPECTED(0x8000FFFF).
Opening the Database Explorer and attempting to attach to the database results in the above as well. There are no apparent locks on the file, etc., and I'm the sole developer for this.
I'm trying to a open a connection to a local database and no matter what I try it just won't work (I'm pretty new to SQL Server and VB for that matter) I tried using 'sqlconnection' with different connection strings but none of them worked or gave me any useful error messages so I tried using 'OleDBConnection' instead, this hasn't worked either and it gives me this error instead:"A first chance exception of type 'System.NullReferenceException' occurred in MyProgram.exe"
Here is the code I am currently trying:
Private Sub MemDetailsSearch_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
ConnectionString = ("Provider = Microsoft.Jet.OLEDB.4.0;" & "Data Source = Database.sdf")
DataConnect = New OleDbConnection(ConnectionString)
[code]....
I installed SQLExpress 2008 on my computer this afternoon and have been trying to create a new database and open a connection to it. I found this code online and tried it:
Dim
conStr As
String =
"Server=MSSMLBIZ;Database=;Trusted_Connection = yes"
[code]....
I want to know what is the right way to close my Database connection while its open.
This is how i open my connection.[code..]
I can't open an Access database on a mapped drive. However it works if I use the UNC path. how I can get this to work? See the code below for an example of what works and what doesn't...
Code:
mConnString = "provider=Microsoft.Jet.OLEDB.4.0;Data Source=\tiger-2000dvb_mt7MTrackBE.mdb" ' This works
mConnString = "provider=Microsoft.Jet.OLEDB.4.0;Data Source=T:vb_mt7MTrackBE.mdb" ' this does not work
Dim objConn As New OleDbConnection(mConnString)
[code].....
The error message I receive is...'T:vb_mt7MTrackBE.mdb' is not a valid path. Make sure that the path name is spelled correctly and that you are connected to the server on which the file resides.I've done the obvious and verified that t:vb_mt7MtrackBE.mdb is a valid path.
I am trying to open an Oracle database connection in vb.net 2008 in order to issue a Select statement and the populate a listbox with it.
My code is as follows:
Dim orclstr As String = _
"Provider=OraOLEDB.Oracle;" & _
"Data Source=10.0.0.77;" & _
"User ID=myuser;" & _
[code]....
Obviously, I am doing something wrong, but I can't figure out what.
I keeping getting an error.Seems to be the connection string.Error happens at connection.Open()
Error Message:Cannot open database "C:UsersJEREDocumentsVisual Studio 2008ProjectsBaseball2009Baseball2009DatabaseBaseball2009.sd"
requested by the login. The login failed. Login failed for user 'JERE-PCJERE'.
Imports System.Data.SqlClient
Public Class Field
Private Sub Field_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load[code]..........
I'm building application that will heavily use database (about 25k query's in few hours) , what is the best way to go:
A) use datareader and open new connection to the database on every client query.
B) load all the needed tables into dataset once the program loaded and use that dataset for the query's?
When using SQL connections in my program, will I have to open and close the connection and the data reader each time I want to access the database ?
[code]...
The fact is I'm making an application, which users can install by using a Setup file...once installed the data in the database can be updated by a centralized server. To do this, they can insert a DVD/CD-ROM and export the necessary data towards it. I need to do it that way, because some of the users who really need this data will be using stand alone computers.The application gets it's data from a mdb-file and the connection remains open as long a person works with the application (maybe not the best way to do, but I know :-) )...when the user uses the application, he can perform an export...this exports the .ini-file and pictures (which works fine), but he also needs to export the mdb behind the application...I already tried connection.close() before and connection.open() after the System.IO.File.Copy...but that doesn't seems to work.
View 2 Repliesi have an application. which is executed after every 5 mins. i have an open connection but it gives me the following error:
ExecuteScalar requires an open and available Connection. The connection's current state is closed.
my code is something like this. I have shown where all i am using ExceuteScalar()
Sub Main()
Try
connection.open()
cmd.ExecuteScalar()
[code]....
What I am trying to do basically is open an access query in a datagrid view and then be able to make changes to the datagrid and then save it back to the database.When I try to save:
Me.BindingSource.EndEdit()
Me.TableAdapter.Update(DataSet)
It says that update is not a member of the tableadapter... Why is that?
i make a class and when i call on form then that error occurs "ExecuteNonQuery requires an open and available connection, the connection Current stat is close "
Class Code isImports System.Data.SqlClientImports System.DataImports System.StringPublic Class DatabaseKits Dim Cn As New SqlClient.SqlConnection Public Function BuildConnection() As Boolean Try Cn.ConnectionString = "Persist Security Info=False;Integrated Security=True;Trusted_Connection=Yes;database=BizAimsPro2008;server=Server-2k3s" BuildConnection =
[code]....
Try If functionmode = "ADD" Then
[Code]...
I got this error..The connection was not closed. The connection's current state is open.
This is coding to add data in Ms access in vb...
Imports System.Data.OleDb Public Class Form1
[Code]...