SQL Insert query, working all day but now fails everytime - c#

What could cause the following error for the very first time when the exact same code (that produces this error) has been working perfectly all day today?
--------------------------- 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)
--------------------------- OK
The code:
this.Cursor = Cursors.WaitCursor;
try
{
// Insert into database
sqlconnection = new SqlConnection(#"Data Source=" + Properties.Settings.Default.DBHost + ";Initial Catalog=BLAHBLAH;Persist Security Info=True;User ID=" + Properties.Settings.Default.DBUserName + ";Password=" + Properties.Settings.Default.DBPassword + ";");
sqlconnection.Open();
SqlCommand cmd = new SqlCommand();
cmd.Connection = sqlconnection;
int count = 0;
foreach (var item in files)
{
cmd.CommandText = #"insert into Images (Name, Games) values ('" + item.Value + "', '" + games + "')";
cmd.ExecuteNonQuery();
count++;
}
}
catch(Exception exception)
{
MessageBox.Show(exception.Message);
}
sqlconnection.Close();
this.Cursor = Cursors.Default;

This is Sql server network connection error. try to login in sql browser also check your sql service is running or not and try to debug your code that are you able to open connection check/login credentials.

Firstly, I'd like to thank everyone for their help and suggestions. I've managed to solve this problem.
As it turns out, the reason this code was failing was because there was an issue with retrieving setting data from Properties.Settings.Default.SettingName. The settings are there and saved, but it wasn't able to retrieve the settings into variables for some reason.
I got this code to work by storing settings somewhere else other than Properties.Settings.

Related

How to restore SQL Server backups using asp.net and C#?

How to restore SQL Server backup using C#?
try
{
string test = "D:\\backupdb\\05012017_130700.Bak";
sqlcmd = new SqlCommand("Restore database EmpolyeeTable from disk='D:\\backupdb\\05012017_130700.Bak'", con);
sqlcmd.ExecuteNonQuery();
Response.Write("restore database successfully");
}
catch (Exception ex)
{
Response.Write("Error During backup database!");
}
Quite weird requerement you have right there. I´ve never heard of someone restoring a database backup from a webpage, and as #Alex K. told, it would be quite rare that the user that uses your web application have the required previleges.
Anyway, supposing that everything told above is OK, the code to restore a backup would be this:
Use this:
using System.Data;
using System.Data.SqlClient;
Code:
private void TakeBackup()
{
var conn = new SqlConnection("Data Source=" + Server + ";Initial Catalog=" + Database + ";User Id=" + Username + ";Password=" + Password + ";");
try
{
conn.Open();
SqlCommand command = conn.CreateCommand();
command.CommandText = "RESTORE DATABASE AdventureWorks FROM DISK = 'C:\AdventureWorks.BAK' WITH REPLACE GO";
command.ExecuteNonQuery();
}
catch (Exception)
{
throw;
}
finally
{
conn.Dispose();
conn.Close();
}
}
This is going to work specifically for the problem you posted. Be sure to set all the parameters of your database server on the connection string, it seems from the comments on your question that you are having communication issues. You have to solve that problems before you do anything. Some tips for that:
Be sure you set all the parameters on connection string the right way
Try to connect using another tool like ODBC so you can test all parameters
Check out SQL Network settings to see if TCP/IP is enabled

After registering to my website instead of inserting the data to the sql server, an error message appears

In my asp website i have a register form that sends data to the database.
When a user enters his data, after submitting, an error is appeared that says:
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)
This is the code:
signup.aspx.cs-
protected void submit_Click(object sender, EventArgs e)
{
string name = Request.Form["name"];
string email = Request.Form["email"];
string password = Request.Form["password"];
string fileName = "Database.mdf";
string sql = "INSERT INTO UserInfo VALUES('" + name + "','" + email + "','" + password + "')";
MyAdoHelper.DoQuery(fileName,sql);
}
MyAdoHelper.DoQuery-
public static void DoQuery(string fileName, string sql)
{
SqlConnection conn = ConnectToDb(fileName);
conn.Open();
SqlCommand com = new SqlCommand(sql, conn);
com.ExecuteNonQuery();
com.Dispose();
conn.Close();
}
MyAdoHelper.ConnectToDb-
public static SqlConnection ConnectToDb(string fileName)
{
string path = HttpContext.Current.Server.MapPath("App_Data/");
path += fileName;
//string path = HttpContext.Current.Server.MapPath("App_Data/" + fileName);
string connString = #"Data Source=.\SQLEXPRESS;AttachDbFilename=" +
path +
";Integrated Security=True;User Instance=True";
SqlConnection conn = new SqlConnection(connString);
return conn;
}
My database name is Database.mdf and its under App_Data Folder
Could anyone tell me what is the problem?
Thx !
A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible.
Above error message clearly suggest that the instance name ".\SQLEXPRESS" is wrong. Please first confirm the instance name.
By the word "registering" I guess you means "Hosted in a webserver". IN that case the connection string most probably won't work that way. We can find the connection string for the SQL server in you hosting providers control panel. Or you can ask them for connection string and mention them that you are using a SQL DB Local file which will be attached with the application. As an example you can provide them your current connection string.

Execute ObdcCommand for NetezzaSQL with C#

I am trying to execute a command with OdbcCommand in c# but it seems i can't even open the connection. This is the data I got to create the Connection String
Server: APPRDNETEZZA (192.168.0.64)
Web Server: beamprdwb3
ODBC DSN Name (64bit): NZ_FUTUREBRANDS
User: MSTR_ADMIN
Port: 5480
This is my code
string connetionString = null;
OdbcConnection cnn;
OdbcCommand cmd;
string sql = null;
connetionString = "Driver={NetezzaSQL}; servername=APPRDNETEZZA ;
database=NZ_FUTUREBRANDS; port=5480; username=MSTR_ADMIN;
password=mstr17Uz1%4;";
sql = "CREATE EXTERNAL TABLE X_STORE_GROUP_GUID_12345(" +
"STORE_ID VARCHAR(10)," +
"STORE_NAME VARCHAR(50)," +
"USERID Varchar(255)," +
"import_guid Varchar(255), )" +
"USING(" +"DATAOBJECT('/apnas01/vol2.nfs.Data/ap_prod/data/store_upload/scripts/12345_guid_12345')" + "logDir '/apps/ap_prod/log'" + " delimiter ','" + " "; ";
cnn = new OdbcConnection(connetionString);
try
{
cnn.Open();
Console.WriteLine("Connection Opened ");
cmd = new OdbcCommand(sql, cnn);
cmd.ExecuteNonQuery();
cmd.Dispose();
cnn.Close();
result = "Executed sucessfully";
}
catch (Exception ex)
{
result = "Error" + ex.InnerException.ToString();
}
The error happens when it tries to open the connection. While debugging it gave me this inner exception
[ODBC Driver Manager] Data source name not found and no default driver
specified
I have the Odbc driver installed in my machine. I dont know it this is happening cuz the connection string is in bad format. I have spent many hours trying to figure it out why doesnt work. Appreciate any kind of help. Thanks
Here is an example Netezza ODBC connection string:
https://www.connectionstrings.com/netezzasql-odbc-driver/
Driver={NetezzaSQL};servername=myServerAddress;port=myPortNumber;
database=myDataBase;username=myUsername;password=myPassword;
Your connection string basically looks the same:
connetionString = "Driver={NetezzaSQL}; servername=APPRDNETEZZA ;
database=NZ_FUTUREBRANDS; port=5480; username=MSTR_ADMIN;
password=xyz;";
SUGGESTIONS:
Make the entire connection string (everything inside the quotes) ONE LINE. Don't break the string into separate lines.
Or use "+" (like you did with your SQL string).
Copy the driver (nsqlodbc.dll?) into the same directory as your .exe assembly (path issue?)
Try both the 32-bit and 64-bit drivers (CPU platform issue?)
Definitely post back what you find!

Unable to connect to any of the specified MySQL hosts

I know that it is an easy problem but I can't find the error. I want to save data in my database. I create a database named "Examen" with Microsoft SQL Server 2008 then in my app in visual studio I make the connection string like this :
string connectionstring = #"Data Source=.\sqlexpress;Initial Catalog=Examen;Integrated Security=True";
Then I use this code to insert data into a "Test" table:
MySqlConnection connection = new MySqlConnection(connectionstring);
MySqlCommand cmd;
connection.Open();
try
{
cmd = connection.CreateCommand();
cmd.CommandText = "Insert into Examen.Test (nom,prenom) values (" + txbnom.Text + "," + txbprenom.Text + ") ";
cmd.ExecuteNonQuery();
MessageBox.Show("ok");
}
catch (Exception)
{
throw;
}
finally
{
if(connection.State == ConnectionState.Open)
{
connection.Close();
}
}
When running this code i had an error when openning the connection
Unable to connect to any of the specified MySQL hosts.
You are mixing MySQL and MSSQL.
Are you sure you want to connect to a MySQL server? Use http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlconnection(v=vs.110).aspx if you would like to connect to MSSQL.
Also you should make yourself familiar with SQL injection

Dropping SQL Server database through C#

I am using this code to delete a database through C#
Int32 result = 0;
try
{
String Connectionstring = CCMMUtility.CreateConnectionString(false, txt_DbDataSource.Text, "master", "sa", "happytimes", 1000);
SqlConnection con = new SqlConnection();
con.ConnectionString = Connectionstring;
String sqlCommandText = "DROP DATABASE [" + DbName + "]";
if (con.State == ConnectionState.Closed)
{
con.Open();
SqlConnection.ClearPool(con);
con.ChangeDatabase("master");
SqlCommand sqlCommand = new SqlCommand(sqlCommandText, con);
sqlCommand.ExecuteNonQuery();
}
else
{
con.ChangeDatabase("master");
SqlCommand sqlCommand = new SqlCommand(sqlCommandText, con);
sqlCommand.ExecuteNonQuery();
}
con.Close();
con.Dispose();
result = 1;
}
catch (Exception ex)
{
result = 0;
}
return result;
But I get an error
Database currently in use
Can anyone help?
Try this:
String sqlCommandText = #"
ALTER DATABASE " + DbName + #" SET SINGLE_USER WITH ROLLBACK IMMEDIATE;
DROP DATABASE [" + DbName + "]";
Also make sure that your connection string defaults you to the master database, or any other database other than the one you're dropping!
As an aside, you really don't need all of that stuff around your queries. The ConnectionState will always start off Closed, so you don't need to check for that. Likewise, wrapping your connection in a using block eliminates the need to explicitly close or dispose the connection. All you really need to do is:
String Connectionstring = CCMMUtility.CreateConnectionString(false, txt_DbDataSource.Text, "master", "sa", "happytimes", 1000);
using(SqlConnection con = new SqlConnection(Connectionstring)) {
con.Open();
String sqlCommandText = #"
ALTER DATABASE " + DbName + #" SET SINGLE_USER WITH ROLLBACK IMMEDIATE;
DROP DATABASE [" + DbName + "]";
SqlCommand sqlCommand = new SqlCommand(sqlCommandText, con);
sqlCommand.ExecuteNonQuery();
}
result = 1;
Here is how you do it using Entity Framework version 6
System.Data.Entity.Database.Delete(connectionString);
You should take a look at SMO.
These allow you to manage all aspects of SQL Server from code, including deleting of databases.
The database object has a Drop method to delete database.
Create sqlconnection object for different database other than you want to delete.
sqlCommandText = "DROP DATABASE [DBNAME]";
sqlCommand = new SqlCommand(sqlCommandText , sqlconnection);
sqlCommand.ExecuteNonQuery();
In this case i would recommend that you take the database offline first... that will close all connections and etc... heres an article on how to do it: http://blog.sqlauthority.com/2010/04/24/sql-server-t-sql-script-to-take-database-offline-take-database-online/
Microsoft clearly states that A database can be dropped regardless of its state: offline, read-only, suspect, and so on. on this MSDN article (DROP DATABASE (Transact-SQL))
Connection pooling at a guess, use sql server's activity monitor to make sure though.
Pooling keeps connections to the database alive in a cache, then when you create a new one, if there's one in the cache it hands it back instead of instantiating a new one. They hang around for a default time, (2 minutes I think) if they don't get re-used in that time, then they killed off.
So as a first go connect straight to master, instead of using change database, as I suspect change database will simply swap connections in the pool.
Add a check routine for database in use (use a connection to master to do it!). You can force the database to be dropped anyway by first executing
ALTER DATABASE [MyDatabase] SET SINGLE_USER WITH ROLLBACK IMMEDIATE
again from the connection to master!
However everybody else using the db, will no longer like you at all...
Just don't use DB name in connection string.
"Data Source=.\SQLEXPRESS;Integrated Security=True;"
I was having the same troubles as Anshuman...
By my testing of the code in question of Anshuman there have been very simple error:
there have to be SqlConnection.ClearAllPools(); instead of SqlConnection.ClearPool(con);
Like this trouble of
"cannot drop database because is in use..."
disappears.

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