ADO.NET: Open SQL Connection - c#

i want to do some sql code run in my webservice in c#
the code is just
[WebMethod]
public void GetCustomers()
{
SqlConnection MyConn = new SqlConnection("Data Source=./SQLEXPRESS;AttachDbFilename=C:/Documents and Settings/Administrator/My Documents/Visual Studio 2008/Projects/WebService2/WebService2/App_Data/Database1.mdf;Integrated Security=True;User Instance=True");
MyConn.Open();
SqlCommand cmd = new SqlCommand();
cmd.Connection = MyConn;
cmd.CommandText = "delete from t1 where name='1'"; //just see ["+month
// [mon+"] it's imp
cmd.ExecuteNonQuery();
}
now i get error like
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)

Correct Format:Server=.\SQLExpress;AttachDbFilename=c:\mydbfile.mdf;Database=dbname; Trusted_Connection=Yes;
Try:
"Data Source=./SQLEXPRESS;AttachDbFilename=C:\Documents and Settings\Administrator\My Documents\Visual Studio 2008\Projects\WebService2\WebService2\App_Data\Database1.mdf; Database=YourDatabasName;Integrated Security=True;User Instance=True"
For more details see:
http://connectionstrings.com/

You might want to check the configuration of your SQL Server as well.
The error remarks the issue could be the named pipes not being active, this is the default setting.
You can always test this fix by going;
Start -> SQL Server xxxx -> Configuration Tools -> SQL Server
Configuration Manager
Where xxxx is the version of SQL Server you are using.
In the tree look at the
-> SQL Native Client xx Configuration -> Client Protocols
Named Pipes is listed.
Set it to being Enabled
Then under
SQL Server Network Configuration -> Protocols for xxxxxx
xxxxxx Being the name of your SQL Server database instance name.
Check that Named Pipes are Enabled there also.
You will need to restart your SQL Server database in order for it to accept Named Pipe calls.
Might be worth a try.

Related

Unable to connect to MySql Server in Visual C#

I am trying to create a local database using MySql in Visual C# but connection is not getting established in the code but when i add the server in the server explorer under data connections its working. I tried test connection it says connection succeeded but its not working in the code.
string connStr = "server=localhost;user=root;database=entry_database;password=superadmin";
con = new SqlConnection(connStr);
This throws an error saying
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)
You cannot use the SqlConnection class to connect to a MySQL server; that is for Microsoft SQL Server only.
Instead, install the MySqlConnector NuGet package and use the following code:
string connStr = "server=localhost;user=root;database=entry_database;password=superadmin";
using (var con = new MySqlConnection(connStr))
{
// ...
}
Your connection string is wrong.. change keys "user" to "Uid" and "password" to "Pwd".
follow eg:
string connStr = "server=localhost;Uid=root;database=entry_database;Pwd=superadmin";
con = new SqlConnection(connStr);
Correct, the format used by you to create the connection string is incorrect, giving you the error you mentioned above.
Actually, the way the connection string is written in MS-SQL is very different from MY-SQL. Every database has its own way of connecting and its individual connection tags:-
Please find the list of connection details for MS_SQL below. This would help you not only in the current mentioned scenario but also will provide a reference for future changes:-
https://www.connectionstrings.com/mysql/

C# SqlConnection stop at method: Open()

String connectionString = "server=127.0.0.1:3306;Database=joonggonara;Uid=root;Pwd=apmsetup;";
SqlConnection sqlConn = new SqlConnection(connectionString);
sqlConn.Open();
SqlCommand sqlComm = new SqlCommand();
sqlComm.Connection = sqlConn;
int a = sqlComm.ExecuteNonQuery();
MessageBox.Show(a.ToString());
I execute in debug mode.
I got 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)
My SQL server version is 5.1.41-community MySQL Community Server
I want to solve this problem
You can't use the SqlConnection class to connect to MySQL Server; it can only connect to Microsoft SQL Server.
Instead, install MySql.Data or MySqlConnector and use the MySqlConnection class.
Additionally, you can't combine the host IP and port into one connection string option. Since the default port for MySQL is 3306, change your connection string to "server=127.0.0.1;Database=joonggonara;Uid=root;Pwd=apmsetup".

How to connect to SQL Server database in VS Express 2012 for Web

I am trying to learn to connect to and perform functions with SQL Server database using C# (out of ASP.NET website). When I try to run
SqlConnection con = new SqlConnection("Data Source=.; database=fengshuidb; integrated security = SSPI");
SqlCommand cmd = new SqlCommand("Select * from emails", con);
con.Open();
to connect I get the following error with the con.Open() instruction.
From VS:
"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)"
What do I need to do to configure connection to database? What security settings do I need? Are there any good resources for this topic?
Try entering the Connection this way
SqlConnection myConnection = new SqlConnection("Database=fengshuidb;Server=[Your_PC_Name]\\SQLEXPRESS;Integrated Security=True;connect timeout = 30");
Where "[Your_PC_Name]" is the name of you local machine if the database is local.
Also take a look at this link:
http://msdn.microsoft.com/en-us/library/jj653752%28v=vs.110%29.aspx
try using SqlConnectionStringBuilder to create a valid Connection String
You missed Initial Catalog in your connection part.
Change it to this:
Data Source=Your sql connection ;Initial Catalog=Your Database name;Integrated Security=True

Connection string for SQL Server?

I am working with SQL Server. I used all connection via :
SqlConnection con = new SqlConnection("data source = .; database = xyzDatabase; integrated security = true");//developed with developer edition.
Now I want to run my application on SQL Server Express, so I used this :
SqlConnection con = new SqlConnection("data source = .\\sqlexpress; initial catalog = xyzDatabase; user id = sa; password = 123");
Point to remember is, I am creating my xyzDatabase at runtime on form load event. But when I execute the program 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: Named
Pipes Provider, error: 40 - Could not open a connection to SQL Server)
(.Net SqlClient Data Provider)
Import the namespaces
using System.Data.SqlClient (if using C#)
or
Imports System.Data.SqlClient (if using VB#)
Your Sql connection object with connection would be like this:
SqlConnection con = new SqlConnection("Data Source=.;Database=xyzDatabase;User Id=sa;Password=admin#123;");
If still your error not resolved, it might be the problem of incorrect installation of MS-SQL SERVER instances.
http://blog.sqlauthority.com/2009/05/21/sql-server-fix-error-provider-named-pipes-provider-error-40-could-not-open-a-connection-to-sql-server-microsoft-sql-server-error/
Hope it might be helpful.
you must active sa user in sql express edition.
SqlConnection cn = new SqlConnection("datasource=.\sqlexpress; initialcatalog=yzDatabase; userid=sa;password=123");

Sql Connection Problem

I have a sqlconnection problem. i have perfectly connection to sql server when i m using sqldatasource.
but when i m try use SqlConnection object throw an exception.
string qstring = "Data Source=****;Initial Catalog=**;User ID=**;Password=**";
SqlConnection con = new SqlConnection(qstring);
con.Open(); (exception thrown here)
exception is : 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)
Sql server is in different machine and i can connect using SqlDataSource object for example i can bind a grid by that way. But i must connect with SqlConnection object
Connection string is true because i have it from SqlDataSource...
Thx for your helps..
You might also want to make sure that the SQL Server is set up to accept remote connections.
(for sql2005 Configuration tools -> Surface AreaConfiguration-> Services and Connections -> database, Local and remote connections )
Is your SQL server is in the same machine ? if yes , Check the SQL server service is running , If its in a different machine,check your development machine has connectivity to it .You can ping to that machine to verify this. You can also check the surface area connection wizard to check whether the SQL server support remote connections , as snomag said
If the code that you have shown is what you have then I'm not surprised that you couldn't connect.
You'll need to have the correct Data Source, UserID and Password in qstring. As it stands asterisk characters won't mean anything.
A new point
A further point, which is often forgotten, SQLConnection will only work with Microsoft SQL Server. If your SQL is provided by a different manufacturer the use OleDBConnection instead.

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