On my prod server, I have 2 instances of SQL server, SQL Server 2000 is the default instance, and I have \SQLEXPRESS2008 as an additional named instance. In my web project, I need to connect to the default, SQL 2000 instance.
I'm using LINQ to SQL in Visual Studio 2008.
In the Server Explorer in Visual Studio, I can create a connection to the DB, see all the tables, correctly generate the LINQ to SQL classes, etc.
In Management Studio I can connect to the DB, see everything, edit, etc.
When I try and run my web project code, however, I get:
A network-related or
instance-specific error occurred while
establishing a connection to SQL
Server. The server was not found or
was not accessible. Verify that the
instance name is correct and that SQL
Server is configured to allow remote
connections. (provider: Named Pipes
Provider, error: 40 - Could not open a
connection to SQL Server)
My connection string in the web project looks like:
<add name="myConnectionString" connectionString="Data Source=myServer.com;Initial Catalog=myDB;Persist Security Info=True;User ID=sa;Password=XXXXX" providerName="System.Data.SqlClient" />
(I'm testing with the sa account out of desperation).
I have other web projects running fine and utilizing the DB, but this is the only one using the LINQ to SQL classes (if that matters)
Help appreciated
Jonathan
If the web server is the same as the SQL server, just use . as the server name; much simpler.
If the web server us not the same as the SQL server, ensure that there is line-of-sight between these servers through any firewalls etc. Also ensure that the server name resolves (in many ways, it is simpler to use the IP address in the connection string if name resolution cannot be guaranteed).
This may be the same thing that happened to me and is one of the most annoying things about LINQ to SQL. Each time you make a change to your dbml, it reverts to the connection used by the server explorer in VS. You must right-click the design surface then manually change the connection back to "myConnectionString", recompile and run.
Related
I have an application using Entity Framework (database first) on top of a SQL Server database. The application is configured with default settings, like I've built all of my applications for the past couple of years.
However, with this particular application, when running on my windows server, I'm getting the following error now and then (quite often):
Exception message: A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified).
The issue never occurs when the application is running locally through Visual Studio (connecting to the same remote SQL Server).
I know for certain that there is no error in the connection string, because as I said, the issue only happens sometimes. Other times it works just fint.
Furthermore, if I copy the entire web.config from the application running on my web server and paste it into my local development environment, it works just fine.
I thought it might be my webserver that was having issues accessing the SQL Server; but the other applications running on the same webserver, accessing the same SQL Server, are all working just fine.
I simply can't figure out what can be causing this, as Ive never experienced anything like it. What am I missing? What should I be looking for?
My connection string:
<add name="MyDbEntities"
connectionString="metadata=res://*/Model.MyModel.csdl|res://*/Model.MyModel.ssdl|res://*/Model.MyModel.msl;provider=System.Data.SqlClient;provider connection string="data source=MyServer\MyInstance;initial catalog=MyDb;integrated security=False;User ID=MyUser;Password=MyPassword;MultipleActiveResultSets=True;App=EntityFramework""
providerName="System.Data.EntityClient" />
As it turns out, the issues were caused by my Owin context. As I don't use the ApplicationUserManager part of owin (I have my own custom tables for authentication), I do not need Owin to set it up for me. However, because I had the following code in my Startup.Auth, owin would try to connect to the DefaultConnection whenever the session expired:
app.CreatePerOwinContext(ApplicationDbContext.Create);
app.CreatePerOwinContext<ApplicationUserManager>(ApplicationUserManager.Create);
app.CreatePerOwinContext<ApplicationSignInManager>(ApplicationSignInManager.Create);
I simply commented out the above (note: I can only do this, because my application does not use the ApplicationUser tables in the database), and it works.
I'm trying to connect to a SQL Server 2008 R2 Express database using a Linq DataContext. The database engine is running on another machine in the local network. We are using SQL authentication, for the time being. SQL Server is set up to allow remote connections.
My connection string looks like this, and works fine. I haven't specified the instance, but it's the only one, so I guess it is chosen by default:
Data Source=192.168.1.50;Initial Catalog=DbName;User ID=SomeUser;Password=SecretPassword;
I've installed the same engine locally too, and this connection string works too:
Data Source=localhost;Initial Catalog=DbName;User ID=SomeUser;Password=SecretPassword;
So does this one, connecting locally:
Data Source=.\SQLEXPRESS;Initial Catalog=DbName;User ID=SomeUser;Password=SecretPassword;
So what if there are multiple instances of the engine running on a remote computer, and I want to specifically refer to an instance?
Data Source=192.168.1.50\SQLEXPRESS;Initial Catalog=DbName;User ID=SomeUser;Password=SecretPassword;
The above connection string yields
Error connecting to database: A network-related or instance-specific error occur
red while establishing a connection to SQL Server. The server was not found or w
as not accessible. Verify that the instance name is correct and that SQL Server
is configured to allow remote connections. (provider: SQL Network Interfaces, er
ror: 26 - Error Locating Server/Instance Specified)
Why doesn't this work? I can't find any examples of a connection string connecting to a particular instance on a remote database engine.
Try this connection string for remote connection:
Data Source=192.168.1.50\SQLEXPRESS,1433;Network Library=DBMSSOCN;Initial Catalog=DbName;User ID=SomeUser;Password=SecretPassword;
Port 1433 should be opened if firewall is used.
And also try to enable remote connection to DbName in sql server management studio.
Even with an IP address, you must specify the instance name.
Aka,
Data Source=192.168.1.50\SQLEXPRESS
is your best candidate there.
Firewalls. You may have to open the PORT NUMBER. But more importantly, you may have to open up the program name.
Note this article:
http://technet.microsoft.com/en-us/library/ms175043.aspx
Note this area in the article:
In the Program dialog box, select This program path. Click Browse, and navigate to the instance of SQL Server that you want to access through the firewall, and then click Open. By default, SQL Server is at C:\Program Files\Microsoft SQL Server\MSSQL11.MSSQLSERVER\MSSQL\Binn\Sqlservr.exe. Click Next.
ALSO:
I like to use this program to "ping" my machine and port. Emphasis on the "and the port".
http://www.microsoft.com/en-us/download/details.aspx?id=24009
I keep that little tool around for doing basic debugging with connection issues.
i am developing a web application in visual studio 2012. and i have added a database file named as Database1.mdf into App_Data folder and i have given following connection string
Data Source=(LocalDB)\v11.0;AttachDbFilename="E:\asp.net mvc\storage\storage\App_Data\Database1.mdf";Integrated Security=True
after that i have written the code for inserting the data but at that i am getting the error like
A network-related or instance-specific error occurred while
establishing a connection to SQL Server. The server was not found or
was not accessible. Verify that the instance name is correct and that
SQL Server is configured to allow remote connections. (provider: Named
Pipes Provider, error: 40 - Could not open a connection to SQL Server)
is there any mistake in the connection string?
Please help me in htis
Usually, for me, this indicates that SQL Server hasn't been configured correctly to receive remote calls. There are three things to check.
Your server instance is named correctly and you have permissions to it
That you are configured to receive remote connections
That SQL server is open on the the protocols you want to use
To check the second one, open up SQL Management Studio and select Properties on the server. Then check under "Connections" that "Remote Server Connections" is enabled.
To check the third, open up SQL Server Configuration Manager and make sure that "Client Protocols" TCP/IP is enabled as well as Named Pipes (depending on your network setup).
Your connection string should be written like this:
connectionString="DataSource=.\SQLEXPRESS; InitialCatalog=Database; AttachDBFilename=|DataDirectory|\Database.mdf; Integrated Security=SSPI;"
I've completed my webpage on my home computer and ready to upload it.
However I'm getting this error:
A network-related or instance-specific
error occurred while establishing a
connection to SQL Server. The server
was not found or was not accessible.
Verify that the instance name is
correct and that SQL Server is
configured to allow remote
connections. (provider: Named Pipes
Provider, error: 40 - Could not open a
connection to SQL Server)
I know the connection string is correct. And I run a few different pages so I can connect to the other databases without problem.
This is the fist time I have used LINQ and I thought perhaps there was a setting it made that I need to change? LINQ is used in my DAL which is separate to the database, its just stored as DLLs in my bin folder...
My development server uses SQL Server 2008 R2 Express and my live server uses SQL Server 2008
I created database scripts to create the database. so I just ran them to downgrade the webpage.
Also In my DAL I just do this:
AHDBcontext db = new AHDBcontext(connectionstring);
var whatever = from s in suppliers
select s;
I always set connection string from the web.config file.
Any ideas?
Check the connection string.
Another way is following.
Go to Start Up => Microsoft Sql server 2008 => Configuratiuon Tools => Sql Server Configuration Manager
Check the Enabled status for client protocol.
restart the Browsing and other necessary services.
i made an app on c# which has database connection and application works fine on my developement pc!
Application starts fine and everything else works fine which has nothing to do with DB but it throw an error when i try to execute query ?
I have Dotnetfx 2.0 installed on target machine what do i need to? Sql server?
Error is:
An error has occured while establishing a connection to the server. When connecting to SQL server 2005, this failure may be caused by the fact that under the default settings SQL Server does not allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified
p.s. its my first db application =S
SQL Server is a completely separate application from the application you wrote and are distributing. If your application does not connect to an existing SQL Server running somewhere on the network you will have to install and configure SQL Server as part of your application's installation.
In addition you will either need to install / create a database as part of your application's installation, or else your application needs to be able to detect the absence of the database and build it itself on first startup.
As Marek said, the connection string is the most likely culprit, and I believe on SQL 2008 you have to explicitly allow TCP connections via:
SQL Server Configuration manager
Select SQL Server Network
Configuration Select Protocols for your instance
Right click on TCP/IP and "Enable"
Make sure your connection string looks something like this:
"Server=(local)\\SQLEXPRESS;Database=Your_DB_Name_Here;uid=sa;pwd=password;"