Can't Open To Connection To SQL Database
Nov 23, 2011
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]....
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May 12, 2005
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
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Jan 17, 2009
i want to know how to open a connection to database from vb.net
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Nov 17, 2009
i 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'.
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Apr 17, 2009
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.
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Jun 22, 2010
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]....
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Dec 31, 2010
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]....
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Apr 26, 2012
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..]
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May 17, 2010
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"))
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May 18, 2009
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.
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Jul 17, 2009
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]..........
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Jul 6, 2009
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?
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Apr 21, 2009
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]...
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May 14, 2010
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.
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Aug 3, 2011
i 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]....
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Nov 30, 2008
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]....
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Dec 19, 2011
Try If functionmode = "ADD" Then
[Code]...
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Jul 5, 2011
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]...
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May 20, 2010
I'm developing a device app in VB.net that will access a SQL Server database. I need to establish a connection when the app is launched, and keep the connection open until the app is closed. I've done the following:In the Master Module:
Public CNN
As SqlConnection
In the Main menu form load:
CNN =
New SqlConnection(sqlConnString)
CNN.Open()
Then when I want to read from the database:
Dim sqlDR
As SqlDataReader
SQL = "SELECT Name FROM Table"
[code]....
When I run the same code without the global CNN, but rather dim the connection inside the Select function, all works well.
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Mar 11, 2010
I'm trying to insert a new records into database, one of those records is a "datetime"...when I type a wrong date, and try to insert those values into database, i get an error (about wrong typed date etc.)...ok, that's fine, things need to work that way. But here comes the problem, I correct the date, and then try to insert values again...here I get an error from the post title. And this doesn't work until I close that form and run it again...here's part of my code:
Dim cvLicence As New SQL
Try
cvLicence.upis("INSERT INTO blabla (itsnotimportant) VALUES ('something')")
MsgBox("everything's fine", MsgBoxStyle.Information)
[code]....
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Jun 12, 2011
Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
exitwithout()
[code].....
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Oct 21, 2009
In my program, I have a timer with a inteval set to 1000ms. The timer is executing a MySQL-command, and right now I'm opening and closing the connection each time.
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Feb 5, 2010
Is there a way to display the connection properties dialog for connection string browsing(for database) in run time?
As I want the user to be able to connect to various database using the GUI.
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Aug 19, 2010
After running the following sub (VS debugger), I try to detach the database in SSMS, but it shows the connection open still and won't let me detach. If I close program in debugger, the database shows no connections. I check the dataadapter's connection in the finally block and is shows closed. What gives
Private Function ClientMasterDBFiles(ByVal MasterClientDBConnection As String, ByVal DBName As String) As DataTable
[Code]...
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Nov 7, 2010
i am using access database for my program. now i have connected to the database in MDI form of main exe, and ir also works, user can log in, it gets verified etc etc etc. now here is the problem, when i load a form from dll and try to use any sql query on that form, i get message, "database connection is not opened". so what i did was, i added the connect() (a function i designed to connect to database) in the load part of the dll's form, it made the trick, query's started to run, everything went fine, and when i reload the form i.e after closing the form, i load it again from MDI form, i get error, connection already open..
[Code]....
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Jan 15, 2012
I am creating a login form together with sql as may databse but when i run may program an error occur at "myData = myCommand.ExecuteReader()" stating that "Connection must be valid and open" what should i do on that to make it fix? [code]
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Jan 14, 2011
I'm trying to connect to a database and keep the connection open for any amount of user activity/queries within the database. Currently I have a connection that opens and closes for any query (save, update, etc...) which requires the logon process to the back-end every time the user saves etc... Is there a way to simply connect and leave the connection open so there won't be a lag time when running the query due to the logon process? This is what I'm using:
Private sConStrFormat As String = "Provider=TDOLEDB;Data Source=TDDEV;Persist Security Info=True;User ID={0};Password={1};Default Database=bcpm_ddbo;Session Mode=ANSI;"
[Code].....
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Dec 28, 2010
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..
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Dec 16, 2011
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?
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Jul 5, 2010
I'm trying to insert data into a mysql database, I'm using xampp as well if thats of any relevance? I keep getting this error: Connection must be valid and open.
on cmd.ExecuteNonQuery()
I'm following my Microsoft Access application that I've also written as a reference and that works perfectly.' This is the code for inserting into an access database which works and is tryed and tested:
Imports System.Data.OleDb
Public Class frmEnterDetails
'text box variables
[code]....
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