I am getting this error while connecting to database , though this error is not seen everytime.
The connection string in c# is as follows,
"Data Source=" + machineName + "\\" + instance + ";Initial
Catalog=dbName;Integrated Security=True";
When i narrowed down the exact place the exception is thrown, it happens to be when database connection open is attempted.
DBConnection.con.Open();
This issue is not reproducible consistenly.
I searched alot and was not able to figure out why this was happenend.I verified the suggestion that was shared,
Verified that instance being used and SQL service is up and running.
TCP/IP is enabled and remote connections are allowed.
Checked the SQL error logs and couldn't figure out anything wrong there.
The connection string has proper format of machinename\instance .
I also restarted the SQL service mutliple times but no luck with that too. I am stuck and do not know how to proceed forward.
Any suggestion is most welcome.
Try connecting to your database from Visual Studio (SQL Server Explorer). Once successful, right-click on the server instance, copy the connection string. Like this, you are sure about the syntax. A database connection is meant to be on a local network. If you connect to a database over internet, implement a webservice.
Have fun :)
Related
i am developing an app where i am having a common sql server database .mdf put on a LAN Server which is needed to be connected to two or more different instances of a same application as other stations.
i am able to select the database but it is giving me and error posted below:
how to overcome this? the connection string is
connectionString = #"Data Source =(LocalDB)\MSSQLLocalDB; AttachDbFilename = " + path + "; Integrated Security = True; Connect Timeout = 30";
P.S. it is working when a single instance is connected to it and it is preventing the second or third app to use it.
any help will be appreciated.
You need to host the database on a network server. Several clients can connect to a SQL Server. But several clients cannot simultaneously connect directly to an MDF file.
The file alone cannot handle the concurrency. You need to have an application for it. That's where SQL Server comes into play.
After hosting, you need to change your connection string as well. Then it should work.
connectionString="Data Source=ServerName;Initial Catalog=DatabaseName;Integrated Security=True;MultipleActiveResultSets=True"
I have a C# WCF project,which contains a database(sql) and webservice,
everything is working fine in the debugger, but once i use the iis(published by file system in vs2015), the webservice cannot make changes in the database,SQL Network Interfaces, error: 50 - Local Database Runtime error occurred
(i am assuming because the connection string is different, current one is:
#"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=C:\Workspace\WebService\WebService\App_Data\Database.mdf;Integrated Security=True";
what would be the correct connection string? or is it something else?
thanks
I have a windows form application in C# and sometimes I want to push some data table from this application to an online mySql server which is hosting all data for my website in PHP. To do that I've installed :
1- MySql for visual studio version 1.2.3
2- MySql Connector.Net 6.9
Also, I have enabled Remote MySql on the server so I can make the connection. I used the '%' wildcard for the meantime because my IP address is dynamic.
my basic c# connection code is as below :
MySql.Data.MySqlClient.MySqlConnection conn;
string myConnectionString;
myConnectionString = "Server=*******;Database=*******;Uid=******;Pwd=********;";
try
{
conn = new MySql.Data.MySqlClient.MySqlConnection();
conn.ConnectionString = myConnectionString;
conn.Open();
MessageBox.Show("connected successfully..");
}
catch (MySql.Data.MySqlClient.MySqlException ex)
{
MessageBox.Show(ex.Message);
}
Unfortunately, every time I run this code I am getting an error which says
"Unable to connect to any of the specified MySQL hosts".
I don't' know where the problem is. Is it something on the UNIX server which
blocks the connections or some other thing which I need to do. I am also new to the CPanel interface and how to deal with it.
I appreciate all the help provided.
Many Thanks.
http://www.codeproject.com/Articles/43438/Connect-C-to-MySQL
Did you see that? You can try it.
I know this is an old question but I had the same issue many years ago and the only way I could get it to work was to enable remote MySql on the server I was running. This basically means allowing remote connections to access the DB. This of course is very risky and poses a major security problem. You can limit connections from specific IPs, but in my opinion its best to have a local DB and then perhaps push updates to an online source somehow.
I am unable to connect to XAMPP localhost in my C# Windows form application.
My code is:
SqlConnection connection = null;
try
{
connection = new SqlConnection("user id=root;" +
"password=12345678;" + "server=localhost");
connection.Open();
}
catch (Exception exptn)
{
MessageBox.Show(exptn.ToString());
}
I made sure to include "using System.Data.SqlClient;" so that my code runs. The timeout error I get at runtime is:
"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."
There was more to the error message, but it was uncopyable and too long to post here. I have tried to install MySql and the .NET MySql connector separately from XAMPP. I added MySql.Data as a reference in Solution Explorer (My research told me to add MySql.Data and MySql.Web, and MySql.Data was the only one listed in the options.). Another source told me to add a Microsoft ODBC Data Source in Server/Database explorer, but the option was not available in Database Explorer. I have made sure XAMPP is running and working properly in phpMyAdmin, and I am able to create tables and run queries there. Many sources also seem to have different opinions as to what is needed in the connection string.
I am completely at a loss as to how I am supposed to connect to localhost databases from another application on the same computer. Forgive me if I am overlooking something basic or if this is a noob question, but I know little about connecting to databases (this type of thing is precisely the reason why). Can anyone help me connect to XAMPP localhost from C#?
Install MySQL Connector from Oracle and then use class MySqlConnection.
Here is the download link -
http://www.mysql.com/products/connector/
Download the driver for ADO.Net and the documentation to use it is here -
http://dev.mysql.com/doc/connector-net/en/connector-net-introduction.html
SqlConnection is for MQ SQL server only and thus it is looking for a instance of MS SQL Server to connect to and it fails to connect since none exists. This explains the error message.
First off I'd like to let everyone know I have searched my particular problem and can't seem to find what's causing my problem.
I have an SQL Server 2008 instance running on a network machine and a client I have written connecting to it.
To connect I have a small segment of code that establishes a connection to an sql server 2008 instance and returns a DataTable populated with the results of whatever query I run against the server, all pretty standard stuff really. Anyway the issue is, whenever I open my program and call this method, upon the first call to my method, regardless as to what I've set my Connection Timeout value as in the connection string, it takes about 15 seconds and then times out. Bizarrely though the second or third call I make to the method will work without a problem.
I have opened up the ports for SQL Server on the server machine as outlined in this article: How to Open firewall ports for SQL Server and verified that it is correctly configured. Can anyone see a particular problem in my code?
string _connectionString = "Server=" + #Properties.Settings.Default.sqlServer + "; Initial Catalog=" + #Properties.Settings.Default.sqlInitialCatalog +
";User Id=" + #Properties.Settings.Default.sqlUsername + ";Password=" + #Properties.Settings.Default.sqlPassword + "; Connection Timeout=1";
private DataTable ExecuteSqlStatement(string command)
{
using (SqlConnection conn = new SqlConnection(_connectionString))
{
try
{
conn.Open();
using (SqlDataAdapter adaptor = new SqlDataAdapter(command, conn))
{
DataTable table = new DataTable();
adaptor.Fill(table);
return table;
}
}
catch (SqlException e)
{
throw e;
}
}
}
The SqlException that is caught at my catch is : "Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding."
This occurs at the conn.Open(); line in the code snippet I have included. If anyone has any ideas that'd be great!
Addendum If I ping the server it's <10ms response time. Additionally I'm getting the same behavior when using SQL Server Management studio (I've just tried this after writing this question as the thought just crossed my mind). I would presume that this has to be a network issue as opposed to a code issue as it also takes two attempts when using SQL Server Management studio. I realise I can implement an error check for connection failure and then re-attempt the connection (I should probably do this anyway) but this doesn't seem particularly 'clean' to me as it doesn't address the underlying problem. Does anyone here have any experience with this issue?
Edit
Although over a year later this question has been viewed over 4000 times, I've since discovered that although I /thought/ the firewall ports were opened, they actually weren't. I'd incorrectly assumed that you need to open the firewall in Windows to the port number that SQL Server uses, in my case I set it to allow connections on TCP port 1433, the firewall caused issues when attempting to establish an initial connection.
I discovered that the correct way to set it up was to set Windows Firewall to allow the SQL Server Instance executable through. To do this you need Add a Program in Windows Firewall, browse to the folder your sql instance resides in such as C:\Program Files (x86)\Microsoft SQL Server\MSSQL10_50.SQLINSTANCE\MSSQL\Binn and then add the sqlservr.exe file to the firewall rules.
You are setting the connection timeout value to 1 second. Drop it from connection string and try again.
Or the problem could be with the SQL select you are using. Could it be taking a long time. If so, the 2nd and 3rd calls would retrieve the cached values and thus run much quicker.