error: 40 - Could not open a connection to SQL Server [duplicate] - c#

This question already has answers here:
Provider named pipes provider error 40 could not open a connection to SQL Server error 2 [duplicate]
(9 answers)
Closed 3 years ago.
Hi I'm writing a simple console application to save XML data into the database using bulkcopy but am currently having problems connecting to my database.
I am getting a SqlException 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 have checked for issues ensuring my SQL server is running and that it's configured correctly. Below is my connection string.
string connectionString = #"Data Source=SYAZANA;Initial Catalog=WangSCM;integrated security=true;" ;
I'm at my wits ends trying to figure out the error, what is the mistake that I'm making?

Follow the steps:
*Go to SQL Server Configuration manager
*SQL Server Network Configuration:
*Protocol for MSSQLSERVER
*In the right pane split page you will have to disable VIA as follows
--->Shared Memory - Enable
--->Named Pipes - Enable
--->TCP/IP - Enable
--->VIA - Disable
Or Try the following
Go to Start -> in search type Services.msc. There you will find services which are available in your system.
There look for -> SQL EXPRESS / SQL Server (SQLEXPRESS) -> Right click on it -> then Start it .
If it is already in Start. Just Stop and start or simply Restart it.

I had the same problem and for some reason I had to add the standard SQL port (1433) and then everything worked again. In your case that would be:
string connectionString = #"Data Source=SYAZANA,1433;Initial Catalog=WangSCM;integrated security=true;"

Related

connecting database to server probably [duplicate]

This question already has answers here:
Cannot Connect to Server - A network-related or instance-specific error
(54 answers)
Closed 3 years ago.
I tried making a site for a school project and when I go ahead and input values in the labels in the register page and send it starts loading for some time and then opens up the code in the server side:
SqlConnection conn = ConnectToDb(fileName);
in this line -----> conn.Open();
and this error msg appears:
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: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)'
You should check your connection string and that you have enough permissions to connect to that database
This is likely because (1) you have the wrong connection string (Example: Wrong server name), or (2) you're loading the connection string from a missing/invalid configuration file. For example, if you're running in debug mode and you your application is trying to load *.debug.config file.
There are other reasons, like you are using NT Authentication and the identity your application is running under does not have SQL Server access.

Connection string for different MS SQL servers [duplicate]

This question already has an answer here:
SQL Server Connection Strings - dot(".") or "(local)" or "(localdb)"
(1 answer)
Closed 5 years ago.
I have several SQL servers in my system:
2017 MSSQLSERVER
2008 SQLEXPRESS
In SSMS I see them like:
GM\
GM\SQLEXPRESS
If I need to connect to SQLEXPRESS I use connection string with . in Server:
connectionString="Server=.;Database=LearnCSharp;Integrated Security=True"
But what does . means in my case and what should be placed in connection string in order to connect to 2017 MSSQLSERVER?
UPD.:
. connects to 2017 server. I have noticed that before computer restart it was connecting to 2008 server
GM connects to 2017 server.
.\MSSQLSERVER generates exception in my application;
System.Data.SqlClient.SqlException (0x80131904): 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: 25 - Connection string is not valid) ---> System.ComponentModel.Win32Exception (0x80004005): The parameter is incorrect
.\SQLEXPRESS and GM\SQLEXPRESS - both connects to server 2008
It means localhost or "this machine"
To specify an instance name, use a backslash after the dot (or computer name):
.\SQLEXPRESS
YOURCOMPUTER\SQLEXPRESS
OTHERCOMPUTER\SQLEXPRESS
etc
Remember when this app is deployed to another machine, the value of "this machine" changes. This may or may not be what you want, so watch for it in future
It's also worth noting that the default SQL Server instance cannot be referenced by name, and if you try to give its name the connection won't work out. If you know you want to connect to the default SQL Server instance (whichever one that is, and there can be only one) then don't put a slash or a name, just a reference to the machine:
.
YOURCOMPUTER
etc
The dot is simply an abbreviated way of referencing your local machine and as highlighted in the following ".\MSSQLSERVER" should do it: SQL Server Connection Strings - dot(".") or "(local)" or "(localdb)").

How to connect to sql server on c# application

I can connect asp.net applications to my databases in SQL Server 2008, however when I try to do the same from Visual Studio in a Winforms application, I always get the 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: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)"
I use the connection string:
SqlConnection Conn = new SqlConnection(#"Server=.\\myserver address\user;Database=testDatabase");
and I get an error when my form loads as that is when I start the connect.
I have gone to my SQL Server Configuration Manager and I get this:
So I do not know what I am doing wrong. There are previous files for older versions of SQL Server in the program files however I do not see how they could affect it...
My sql services
I would also like to add that I added sql server to the firewall exceptions already
You should consider using connection with following syntax
Server=myServerName\myInstanceName;Database=myDataBase;User Id=myUsername;
Password=myPassword;Integrated Security=SSPI;
OR
Server=myServerName\myInstanceName;Database=myDataBase;Integrated Security=true;
When using current Windows account credentials
OR on local Server with default Windows authentication
Server=myServerName;Database=myDataBase;Integrated Security=true
(this was solution that worked for OP)
And for #"Server=.\\myserver using # before string means that no character would escape that string so
\\ without # turns into \
\\ with # stays \\
check C# '#' before a String
For more information about connection strings please visit connectionstrings.com
Check whether these services has been started or not as shown in below snapshot
..
If then try to start them and please try to connect your database.
Please try to use the folowing command:
I can see that you may have a problem with MOF.
mofcomp.exe "C:\Program Files (x86)\Microsoft SQL Server\100\Shared\sqlmgmproviderxpsp2up.mof"

Error - "The server was not found or was not accessible" when trying to connect to sql server database

I'm working on a local project and trying to connect to a local database.
I have this class in it the connection string:
public class SQLConnection
{
public static string connectionString =
#"Data Source=TZVIKA-PC\SQLEXPRESS;Initial Catalog=WorldCup;Integrated Security=True";
public static WorldCupDBDataContext wcDataContext =
new WorldCupDBDataContext(connectionString);
public static WorldCupDBDataContext GetDataContextInstance()
{
return wcDataContext;
}
}
when I try to execute this line in a windows form:
teamBindingSource.DataSource = database.Teams.OrderBy(team => team.TeamId);
I get the following sql exception:
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)
My friend ran the code and it works on his pc(when changing the connection string of course to a relevant one)
Why is it not working for me?
A good (and easy) way to test if your SQL connection is working is to use a .UDL file. Simply create an empty text (.txt) file on your desktop and rename the extension to .udl. Double click and you'll be presented with a SQL connection window, fill in the details, test connection and then (when it's working) save. Close the window and rename the file extension to .txt. Open and inside you'll find your working connection string.
Enable remote connections for SQL Server Express 2012
Most common problems are:
1) Your sql server express is not running. Check it in "sql server configuration manager"
2) server runs but don't allow remote connection. Use sql management studio to configure it.

cannot connect sql server 2008 from another computer [duplicate]

This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
System.Data.SqlClient.SqlException A network-related or instance-specific error
i have winform application in c# which connect to my own db and its working fine my current sql connection string is :
SqlConnection con = new SqlConnection("Data Source=ITPL_PC1;Initial Catalog=Data_Project;Persist Security Info=True;user id=sa;Password=insforia");
but when i am taking this winform to another computer its not working .. then i am changing my connection string to :
SqlConnection con = new SqlConnection("Data Source=192.168.0.28\\ITPL_PC1;Initial Catalog=Data_Project;Persist Security Info=True;user id=sa;Password=insforia");
but its not working ...
i have changed all the settings in sql server of remote access but still it showing an error
Sql Exception was unhandled
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)
is my connection string is wrong? what it should be?
pls help me out
Data Source=ITPL_PC1
Identifies a server called ITPL_PC1. You're connecting to the default instance on this server.
Data Source=192.168.0.28\ITPL_PC1
Identifies an instance called ITPL_PC1 running on a server with IP address 192.168.0.28. We don't know the name of this server.
If the instance you want to connect to is the default instance on ITPL_PC1, then the first version should always work (provided ITPL_PC1 can be resolved).
The Windows security might be preventing the access. You can try the below.
1.Go to the service management console of windows by typing services.msc in the run window.
2. In the window displayed you can see a list of services. From the list find out Base Filtering Engine.
3.Right click and stop it. Its done
I have fixed the same issue like this after lot of googling.(For me it was not working even after enabling TCP/IP from sql configuration manager)
First you open SQL managnebt studio and connect to another pc sql server :
Please follow bolew step :
Strat -> program -> window sql server 2008 -> configuration tools
--> sql server Configuration manager -->
Start sql server browser service
-----------
Next --->Sql serverNetework COnfiguration --> Enable all Protocls and
also Sql Native Client.. --> Enable all Protocls then
--------------
reatsrt all service and connect to sql
-------------------------------------------------
If you get connection then SQL Database to connect database from visual studio from there to find connection string and copy and paste to connection string.

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