Hi I am trying to connect to a local SQL Server Compact database (.sdf) in a Windows forms project and have been facing this problem for quite some time. I am not allowed to use datasets for the project, all the queries and connections are written in the application.
System.Data.SqlClient.SqlException
A network-related or instance-specific error occurredwhile 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)
Code:
SqlConnection _Connection = new SqlConnection(ConfigurationManager.ConnectionStrings["restaurant"].ToString());
SqlCommand _Command = _Connection.CreateCommand();
_Connection.Open(); // <- throws exception
To connect a Sql Server Compact you need a different set of classes contained in the namespace SqlServerCe (SqlCeConnection, SqlCeCommand and so on....)
SqlCeConnection _Connection = new SqlCeConnection(ConfigurationManager.ConnectionStrings["restaurant"].ToString());
SqlCeCommand _Command = _Connection.CreateCommand();
_Connection.Open();
of course, you need to reference the assembly that contains the above mentioned classes.
System.Data.SqlServerCe.dll (ADO.NET provider)
and add the using statement
using System.Data.SqlServerCe;
Related
I have this connection string and working well when I test my aplication from the same SQL Express, I have an instance called DOKUSTAR.
using (SqlConnection conn = new SqlConnection(#"server=.\DOKUSTAR;Database=RdaDB10;Trusted_Connection=Yes"))
using (SqlCommand comm = new SqlCommand(#"select top(1) pais, clase, operation from Document_Class where codigoafip = #codafip", conn))
The problem is when I tried to connect from outside of the server does not works the connection and show me the following messages:
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).
Any suggestions will be greatly appreciated.
.\DOKUSTAR refers to an instance of DOKUSTAR on the current machine.
You need to change it to MACHINE_NAME\DOKUSTAR
I am running a local mysql database on my computer using wampserver. I have made a c# console application that I want to use to update values in a table. However I am having issues connecting to the database. My password is an empty string.
string user = "John Doe";
string queryString = "UPDATE users SET is_awesome=1 WHERE user=#a1";
string connectionString = "Server=localhost;Database=mydatabase;User Id=root;Password=;";
SqlConnection connection = new SqlConnection(connectionString);
connection.Open();
SqlCommand cmd = new SqlCommand(queryString, connection);
cmd.Parameters.Add("a1", user);
cmd.ExecuteNonQuery();
However when I attempt to run this code I get the following error:
System.Data.SqlClient.SqlException
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)'
Inner Exception
Win32Exception: The system cannot find the file specified
I believe my database allows remote connections because I am able to connect to it using a different php application I am running. How can I connect to a sql database from c# and run my query?
You must connect to MySql witch is specific for MySql Like MySqlConnection for more look this tutorial
or this
I've made a code that create the database automatically in the folder where the software is executed. The DB was created succesfull, but when I create the object for the connection this exception is displayed:
System.Data.SqlClient.SqlException (0x80131904): There was a network error or specific instance while trying to establish 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) ---> System.ComponentModel.Win32Exception (0x80004005): Can not find the file specified
on this line:
con.Open();
but the problem I think is on this declaration of the connection:
static SqlConnection con = new SqlConnection(
"Server=localhost;Database=AppDB.sqlite;");
What am I doing wrong?
UPDATE Details:
SqlCommand command = new SqlCommand(#"INSERT INTO Team (name,code, shortName, squadMarketValue,
crestUrl, link_self, link_fixtures, link_players, caption) VALUES (#name,
#code,#shortName,#squadMarketValue,#crestUrl,#link_self,#link_fixtures,
#link_players,#caption)", con);
How you can see I'm using parametizer query, and if I use this object:
static SQLiteConnection m_dbConnection = new SQLiteConnection("Data Source=SoccerForecast.sqlite;Version=3;");
the con variable is underlined in red, an the compilers tell me:
it is not possible to convert SqliteConnection in SqlConnection
Your connection is wrong. You didn't specified the kind of database you're trying to connect to in your question. There's a mention of SQLite while your are using an sql connection object. The sql connection object is for connection to the ms sql server database. If you really want to connect to an ms sql server database, you'll need to change the connection string to provide a username / password or a Trusted_Connection=True to use your windows account.
However, if the database you are trying to connect to is an SQLite DB, you will have to use a different connection object. This and this SO question has answers about available libraries and examples that will explain how to create a connection to a SQLite database.
The site connectionstring.com is also a good resource when you need to generate a connection string.
I've got an SQL server and database setup on an external server (let's call the domain name "hello.com" for the purposes of this), and I want to connect to this server via a C# program. So far I have this (All server/database details are different to the real ones):
private static void SetupSQL()
{
string connectionString = "server=hello.com; database=db1; uid=user1; pwd=xxxxx;";
connection = new SqlConnection();
connection.ConnectionString = connectionString;
try
{
connection.Open();
Console.WriteLine("Connected");
}
catch (Exception e)
{
Console.WriteLine(e.Message.ToString());
}
}
This is giving me an error 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: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server)
I have checked all the connection string, and I am allowed remote access, as I have SQLWorkbench open querying the database right now on the same computer.
Any ideas?
You'll need the MySQL driver:
http://dev.mysql.com/downloads/connector/net/
You can then use the the MySqlConnection connection class to connect.
MySqlConnection connection = new MySqlConnection(connectionString);
http://www.codeproject.com/Articles/43438/Connect-C-to-MySQL
You can't use SqlConnection object to connect to MySQL database, you should use MySqlConnection instead after you import its dll
I'm trying to create a database in SQL Server Express using WinForms and C#
Here is what I'm trying to do
Microsoft.SqlServer.Management.Smo.Server srv = new Microsoft.SqlServer.Management.Smo.Server srvServer();
int i = srv.Databases.Count;
just to get the count at the start. But I 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: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server) this is the stack track
at Microsoft.SqlServer.Management.Common.ConnectionManager.Connect()
at Microsoft.SqlServer.Management.Common.ConnectionManager.get_ServerVersion()
at Microsoft.SqlServer.Management.Smo.ExecutionManager.GetServerVersion()
at Microsoft.SqlServer.Management.Smo.SqlSmoObject.GetDbComparer(Boolean
inServer)
at Microsoft.SqlServer.Management.Smo.SqlSmoObject.InitializeStringComparer()
at Microsoft.SqlServer.Management.Smo.AbstractCollectionBase.get_StringComparer()
at Microsoft.SqlServer.Management.Smo.SimpleObjectCollectionBase.InitInnerCollection()
at Microsoft.SqlServer.Management.Smo.SmoCollectionBase.get_InternalStorage()
at Microsoft.SqlServer.Management.Smo.SmoCollectionBase.InitializeChildCollection(Boolean
refresh)
at Microsoft.SqlServer.Management.Smo.SmoCollectionBase.get_Count()
at CreateDB.CreateDB.btnCreateDB_Click(Object sender, EventArgs e) in C:\Users\Guest1\Downloads\CreateDB\CreateDB\CreateDB.cs:line 82
What should be done?
If you're using SQL Server Express, and you've installed with all the defaults, then your server instance will be called .\SQLEXPRESS. You need to use that in your code:
using Microsoft.SqlServer.Management.Smo;
Server srv = new Server(".\\SQLExpress");
int i = srv.Databases.Count;
If you create a new Server instance without specifying an instance name, it tries to connect to the default instance (with no name) - which you don't have, if you've installed just SQL Server Express.
First make the connection by using the SqlConnection object. you should do this
SqlConnection conn = new SqlConnection(#"Data Source=.\SQLExpress;Initial Catalog=master;Integrated Security=True");
Microsoft.SqlServer.Management.Smo.Server server = new Microsoft.SqlServer.Management.Smo.Server(new ServerConnection(conn));
int i = server.Databases.Count;