i have finished a desktop c# project in which i make use of Entity framework 5 and SQL server 2008
in my machine it's working well, but i created a virtual machine and tried to deploy it there and I have problems.
I get this error : System.Data.EntityException: The underlying provider failed on Open. --->
System.Data.SqlClient.SqlException: 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.
I used installshield for the setup and I have installed sql express in the visrual machine, during the setup I create the database and all the tables.
my connection string is this :name="BussinessContainer" connectionString="metadata=.\Bussiness.csdl|.\Bussiness.ssdl|.\Bussiness.msl;provider=System.Data.SqlClient;provider connection string="data source=localhost;initial catalog=yingyangDB;User ID=username;Password=password;integrated security=True;MultipleActiveResultSets=True;App=EntityFramework"" providerName="System.Data.EntityClient"
Should I change the connection string?
I searched a lot before posting this, but nothing worked..any help?
SQL Express (normally) doesn't create as a "Default instance" - i.e. connecting by localhost isn't sufficient to connect to the local SQL express instance.
You may need to use localhost\SQLExpress to connect to the local SQL Express instance (the instance name may be different, but usually it is not.
Additionally, you specify an Initial Catalog in your connection string, which I assume is pointing at your new DB. However you say that you create the DB during the installation - so that DB may not actually exist in your Instance yet. That may be causing it to fail out. Try taking it out of the string and see if that lets you connect.
Related
This question already has answers here:
Cannot Connect to Server - A network-related or instance-specific error
(54 answers)
Closed 6 years ago.
I'm new to ASP.NET MVC and was just messing around with it and trying to see how it works. So I decided to make a query to the database accessed with the default ApplicationDbContext. Normally, if the database hadn't been instantiated before that, this query would make sure to first create the database and then make the query, right? Well, here's what I did:
// This is the default Index action in the Home controller:
public ActionResult Index()
{
var db = new ApplicationDbContext();
var usersCount = db.Users.Count();
return View();
}
I know that the query is pretty meaningless but the sole purpose of it was for it to generate the database. The thing is it that it doesn't. I get a System.Data.SqlClient.SqlException when trying to execute the query (second line of the method).
Even when checking the App_Data folder I see that the database isn't created. What could be the cause of this? Strange thing is that this works on my desktop computer, but not on my laptop. But I did notice that when I put an invalid Data Source(ex. Data Source=.) in the connection string I get the same exception on my desktop computer. So maybe something is happening with the LocalDb that's causing this behaviour.
The connection string:
<connectionStrings>
<add name="DefaultConnection" connectionString="Data Source=(LocalDb)\MSSQLLocalDB;AttachDbFilename=|DataDirectory|\aspnet-DefaultProject-20160731061747.mdf;Initial Catalog=aspnet-DefaultProject-20160731061747;Integrated Security=True" providerName="System.Data.SqlClient" />
</connectionStrings>
This is the full exception:
An exception of type 'System.Data.SqlClient.SqlException' occurred in EntityFramework.dll but was not handled in user code
Additional information: 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: 52 - Unable to locate a Local Database Runtime installation. Verify that SQL Server Express is properly installed and that the Local Database Runtime feature is enabled.)
I would be very grateful if someone can come up with a solution for this!
P.S: Everything works fine on my laptop if I change the Data Source to my SQL Server Express server name.
Sounds like your LocalDb instance isn't installed. This is a bit of a "dev attachment" version of SQL that's installed with certain versions of Visual Studio and might have been de-selected or just plain not included perhaps if the original install was older and has gone through upgrades, etc.
This post gives a decent explaination: How to install localdb separately?
Basically google for SqlLocalDb.msi and follow the instructions.
I generally prefer Express over localDb anyway, but that's up to you.
Also note that connection strings are considered "loose" information in the web.config for MVC stuff. That is, they tend to be specific to the machine, so if you're changing machines (or working on a team), your machine is likely to have a different connection string (or a local copy/partial of web.config).
I've built an .asmx web service which retrieves informations from a local sql server 2014 database.
Everything is working fine on localhost, but after publishing the web service to Azure i get the error:
An unhandled exception of type 'System.Web.Services.Protocols.SoapException'
occurred in System.Web.Services.dll
Additional information: Server was unable to process request. ---> 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)
SQL Server is configured to allow remote connections.
My connection string is like:
string con2 = #"Data Source=OfficePc\MSSQLSERVER2014;Initial Catalog=Database;Persist Security Info=True;User ID=Admin;Password=123456";
Is the error the result of something missing from the connection string, or am i missing some configurations changes?
As Paul mentioned in a comment under the question, your connection string is pointing to a local database resource (presumably on your dev machine). Even though you configured your local database server to support remote connections, the address OfficePc\MSSQLSERVER2014 isn't addressable, as that does not equate to a machine address (IP address).
Your app would need to connect to your database via an accessible IP address (which might require you to do some port-forwarding on your local network, or open ports on your firewall).
Alternatively, you can migrate your database to Azure (either with SQL Server in a VM or with the SQL Database service).
Keep in mind: If you are accessing a local (on-premises) database server from Azure, there will be latency added, as well as some outbound bandwidth costs.
It looks like SQL Server instance is not running or not accessible. Try connecting to the same database using SSMS and if you get the same error then the instance is not running.
Mostly the error occurs when the Database server was not found. Recheck if the server name (Data Source) is mentioned correctly. If you manually generated the connection string use .uld file to generate connection string.
To auto generate connection string using .udl file:
Create a sampe.txt file.
Rename it as sample.udl file.
Then double click on it, It will show you window entitled 'Data Link Properties'.
Configure the connection there.
Then Test the connection using test connection button.
Then open the file with notepad. It will show you the exact connection string.
For further reference check : MSDN
I have a database called Library created in SQL Server 2014 under my locally created server instance. I am using that database as the datasource in my windows form application. It is working perfectly when on my computer, but when I run it on other machines, it stops with the error
Unhandled exception occurred...
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 connection to SQL Server)
I have started all services from configuration manager and have enabled tcp/ip under protocols for MSSQLSERVER. Is there any way I can accomplish this, or do I have to shift to local db?
Make sure that your connection string includes your remote machine name as part of the "Data Source", so something like :
connectionString="Data Source=machinename\SQLExpress;Initial Catalog=mydbname;Integrated Security=True"
note that this connection string will target a db name "mydbname", under the machine machinename which has a SQL Express instance.
if that didn't work let me see your connection string.
I've got an C# .Net 3.5 executable that runs on a local machine and makes database calls to a server running SQL Server 2005. I've added a System DSN using the Data Sources manager on the local machine called "localserver" (with the driver set to SQL Server). When I create the DSN, I can test the connection to the server successfully.
I've added localserver to my connection string in my executable, and I get an 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)"
The server I am connecting to does allow for remote connections. When I replace localserver with the server name, it connects fine, but this program will be at multiple locations with multiple server names, so I need to make the data source dynamic.
Any ideas as to why this is happening?
Thank you,
Aaron
EDIT:
I've also tried using "localserver,1433" as my data source, but I get 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: TCP Provider, error: 0 - No such host is known.)"
EDIT:
Thank you for your responses. To solve my problem, I made a small method to gather the servername using an odbc connection.
I can then send the servername to the SqlConnection. Thanks again for your input.
SqlClient (ie. SqlConnection) has absolutely nothing to do with ODBC. As such using an ODBC Data source Name in the SqlClient connection string will get you nowhere fast.
You can configure the server name in app.config and build the connection string using SqlConnectionStringBuilder. At deployment, you change the exe's or the user's .config file appropriately.
As Remus said, DSN has nothing to do with SqlConnection. Instead use this connection string:
http://www.connectionstrings.com/sql-server-2005#1
Also read this:
http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlconnection.connectionstring.aspx
An Excerpt from the above post:
To connect to a local computer,
specify "(local)" for the server. If a
server name is not specified, a
connection will be attempted to the
default instance on the local
computer.
I would repeat that SqlConnection has nothing to do with DSN,
I am using VSTS 2008 + .Net 3.5 + C# + SQL Server 2008 Enterprise on Windows Server 2003. I am using the following connection string, and labtest1 is the local machine name and I connect from local machine using ADO.Net. Then it always fail with connection error. But when I change in the connection string from "labtest1" to ".", connection has no issue with the same ADO.Net client code. Any ideas what is wrong?
Data Source=labtest1;Initial Catalog=CustomerDB;Trusted_Connection=true;Asynchronous Processing=true
Here is the detailed error message I got,
System.Data.SqlClient.SqlException: 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)
Looks like a Sql Server configuration issue to me : have you tried to tune protocols in Sql Server Network configuration ? Named Pipes or TCP/IP should be enabled.
When you use "." or "(local)" it connects to the default instance on your PC, perhaps the SQL Server was installed with instances, in which case you have to specify the instance name in the connection string in the format "SERVER\INSTANCE_NAME".
In SQL Management studio execute this query to see your full server\instance name
select ##servername
I have seen this issue previously with ZoneAlarms blocking the connection (on the machine trying to connect to the SQL server). I would spend some time investigating this area around firewalls etc.
Hope this helps
Do you have the Named Pipes network protocol enabled in the network config? (In the SQL Server Configuration Manager - sql server 2005, that's what I have, might be different in 2008 - you should be able to verify this setting)
Try to ping by the computer name: ping labtest1. if it does not find the server, then try ping labtest1.mydomainname.com with the domain name. If this works, then you just need to add/fix the DSN aliases in the domain controller or just re-login to the machine.
One other thins - and may not be relevant - but you've not specified the security model, at least not in the string provided as a sample.
I would expect to see: Integrated Security=True (given that its the local machine) in the connection string.
The other thing that may be relevant is - as has already been mentioned - the protocols, I'd look to make sure that TCP/IP is enabled.