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How to convert ASP.NET Core code to access SQL Server to work with local SQLite DB?

I've been developing my web application to work with a SQL Server database hosted on Azure. To interface with it, I've been using code similar to the following:
SqlConnection scn = new SqlConnection(GetConnectionString());
SqlCommand cmd = new SqlCommand("Select page_name from Pages where page_name = #page_name", scn);
cmd.Parameters.AddWithValue("#page_name", pageName);
try
{
scn.Open();
string ret = Convert.ToString(cmd.ExecuteScalar());
scn.Close();
return ret;
}
catch (Exception er)
{
throw er;
}
finally
{
if (scn != null)
{
if (scn.State != System.Data.ConnectionState.Closed)
{
scn.Close();
}
scn.Dispose();
}
}
Now that I've realized that I can use a local SQLite database, I'm trying to switch over to that, since there is no reason for this application to need a DB server. I've put in this new connection string:
Data Source=test2.db;
But I get an error:
An unhandled exception occurred while processing the request.
ExtendedSocketException: No such device or address
System.Net.Dns.InternalGetHostByName(string hostName)
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: TCP Provider, error: 35 - An internal exception was caught)
It looks like it's still trying to connect to a SQL Server. How can I make it use the local SQLite database that I put in the connection string?

I figured it out, it was way simpler than I thought it would be.
Install the NuGet package System.Data.SQLite.
Replace all of the instances of SqlConnection, SqlCommand, SqlDataAdapter, etc. with their SQLite equivalents (eg. SQLiteConnection, SQLiteCommand, SQLiteDataAdapter).
In Startup.cs, change options.UseSqlServer to options.UseSqlite.

error connection to database c#

I'm trying to connect to a database from VS2017
var str = str1.ConnectionString =
"Data Source=141.*****.199;" +
"Initial Catalog=****;" +
"User id=***;" +
"Password=****;";
using (SqlConnection conn = new SqlConnection(str))
{
try
{
conn.Open();
var text = "SELECT * FROM Users u WHERE u.Id=76769";
...
}
catch (Exception e)
{
return req.CreateResponse(HttpStatusCode.OK, e.ToString());
}
and get 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.
It's azure function. If I set this connection from LogicApp, then there are no errors.
Why the connection does not work from the azure-function?

can someone help. Functions refer to the database not with only ip , which are listed on the portal. They have several variants. And on the portal these addresses do not look, only through https: //resources.azure.com. And yes, you just need to specify in the firewall all valid values

I am connecting to an SQL DB from Azure Function, and I noticed a little difference in connection string that I am using.
Pls try and see if it works for you:
"Server=tcp:141.*****.199,1433;Initial Catalog=****;User ID=*****;Password=*****;"
1433 - is the default MS SQL port number.

Connecting to SQL Azure with ADO.NET

Hi I try to connect to a SQL AZURE DB with ADO.NET.
Here is my code:
private static string userName = "<**#********>";
private static string password = "<********>";
private static string dataSource = "<******.database.windows.net>";
private static string databaseName = "<******>";
public void Save()
{
SqlDataReader queryResultCloud;
string queryString = "select * from tblScan";
SqlConnectionStringBuilder connString2Builder;
connString2Builder = new SqlConnectionStringBuilder();
connString2Builder.DataSource = dataSource;
connString2Builder.InitialCatalog = databaseName;
connString2Builder.Encrypt = true;
connString2Builder.TrustServerCertificate = false;
connString2Builder.UserID = userName;
connString2Builder.Password = password;
using (SqlConnection connection = new SqlConnection(connString2Builder.ConnectionString))
{
SqlCommand command = new SqlCommand(queryString);
command.Connection = connection;
connection.Open();
queryResultCloud = command.ExecuteReader();
connection.Close();
}
and I get next 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)

Your code seems to be correct. One thing to try is to set TrustServerCertificate to true, and see if it works. Note it is recommended to set this property to false when Encrypt is set to true. But there’re reports that combination cause connection issues. I would like to suggest you to check http://www.wadewegner.com/2010/08/using-the-trustservercertificate-property-with-sql-azure-and-entity-framework/ for more information. In addition, check again if you have configured SQL Azure firewall to allow connection to your local machine. If you’re behind a proxy, it is needed to add your proxy’s IP address to the firewall exception.
Best Regards,
Ming Xu.

You're likely behind a proxy that doesn't allow outbound connections to port 1433, which is the only port you can use with SQL Azure:
The Windows Azure SQL Database service is only available with TCP port
1433. To access a SQL Database database from your computer, ensure that your firewall allows outgoing TCP communication on TCP port 1433.
I'm in this situation as well, and the most promising / challenging solution appears to be this port bridging application technique, but the solution itself is dated and needs an older version of VS than I have installed, so I'm looking at some other alternatives.

Connection String in c#

I am trying to connect to a database with my connection string and recieve the following error when trying to connect to the database. For intergrated Security I user SSID so I don't have to enter a username and password. Also, the database resides on the same machine and was created inside VS2010. I can connect to the db without a problem using the SqlDataSource, but I am looking to start writing my own connection strings.
protected void btnUpdate_Click(object sender, EventArgs e)
{
string source = "server=(local)" + "integrated security=SSPI;" + "Connect Timeout=30; " + "database=Name";
SqlConnection conn = new SqlConnection(source);
conn.Open();
conn.Close();
}
The Error I get is this:
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)

Try the following syntax as connection string:
string source = "Data Source=Server Address;Initial Catalog=Database Name;Integrated Security=SSPI;";
Where Server Address should be localhost or .\SQLExpress
Hope thats correct. I have'nt installed a vs for testing

You are missing a ; after the server name.
Why are you concatenating all the parts of the connection string if they do not change? It makes it more difficult to read.
Try this:
string source = "server=(local);integrated security=SSPI;ConnectTimeout=30;database=Name";

You need a semicolon after (local)
string source = "server=(local);" + "integrated security=SSPI
I notice you tagged the question with asp.net
by default asp.net runs under a system account, when you are using integrated security then that account is trying to access your database, it probably doesn't have permission.
Take a look here for some information.

I would recommend you to use the SqlConnectionStringBuilder: http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlconnectionstringbuilder(v=VS.100).aspx
That will probably make it easier.

To connect to SQL Server from C#.NET, you need to create a connection string such as below:
private SqlConnection connection;
private string connectionString =
#"Server=(local);Database=Embedding_SQL_Test;User ID=sa;Password=123";
connection = new SqlConnection( connectionString );
Next, you use the SqlConnection object created above to create a 'SqlCommand', as shown below:
SqlCommand cmd = new SqlCommand( "select * from Customer where CustomerID = #Cid",
connection);
The SQL query shown here can be replaced by a SELECT, INSERT, UPDATE queries etc.
Next to execute the SQL queries in the database, you use the following methods:
ExecuteReader - to execute SELECT queries
ExecuteNonQuery - to execute INSERT, DELETE, UPDATE, and SET statements.
This is a very short description of how to connect to SQL Server database from C# and execute SQL queries in the database.
For details about the connection string, the methods and their parameters check the following link: ( http://www.shahriarnk.com/Shahriar-N-K-Research-Embedding-SQL-in-C-Sharp-Java.html )
Here you will also find details about how to pass parameters to the SQL queries as well as calling stored procedures and much more.

Login function runs different between local and server

Here is my check login function:
protected bool checkLoginStatus(String email, String password)
{
bool loginStatus = false;
bool status = false;
try
{
Connector.openConn();
String str = "SELECT * FROM [User]";
SqlCommand cmd = new SqlCommand(str, Connector.conn);
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataSet ds = new DataSet();
da.Fill(ds, "tblUser");
//check valid
foreach (DataRow dr in ds.Tables[0].Rows)
{
if (email == dr["Email"].ToString()
&& password == Connector.base64Decode(dr["Password"].ToString()))
{
Session["login_status"] = true;
Session["username"] = dr["Name"].ToString();
Session["userId"] = dr["UserId"].ToString();
status = true;
break;
}
}
}
catch (Exception ex)
{ }
finally {
Connector.closeConn();
}
return status;
}
And call it at my aspx page:
String email = Login1.UserName.Trim();
String password = Login1.Password.Trim();
if (checkLoginStatus(email, password))
Response.Redirect(homeSite);
else
lblFailure.Text = "Invalid!";
I ran this page at localhost successful!
When I published it to server, this function only can run if email and password correct! Other, error occured:
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 tried open SQL Server 2008 Configuration Manager and enable SQL Server Browser service (Logon as:NT Authority/Local Service) but it stills error.
(note: here is connection string of openConn() at Localhost (run on SQLEXpress 2005)
connectionString="Data Source=MYLAPTOP\SQLEXPRESS;Initial Catalog=Spider_Vcms;Integrated Security=True" />
)
At server (run on SQL Server Enterprise 2008)
connectionString="Data Source=SVR;Initial Catalog=Spider_Vcms;User Id=abc;password=123456;" />
anyone have an answer for my problem :(
thanks a lot!

That's a pretty strage behaviour.
First of all, on what line is exception thrown? When calling Fill()?
Also. Was identity impersonation used previously and is still on (although I can't see direct relation here, but whatever...)?

This mybe caused by the fact that SQL Server 2005 Express Edition does not allow remote connections by default:
From http://support.microsoft.com/kb/914277
Click Start, point to Programs,
point to Microsoft SQL Server 2005,
point to Configuration Tools, and
then click SQL Server Surface Area
Configuration.
On the SQL Server 2005 Surface Area
Configuration page, click Surface
Area Configuration for Services and
Connections.
On the Surface Area Configuration
for Services and Connections page,
expand Database Engine, click Remote
Connections, click Local and remote
connections, click the appropriate
protocol to enable for your
environment, and then click Apply.
Note: Click OK when you receive the following message:
Changes to Connection Settings will
not take effect until you restart the
Database Engine service.
On the Surface Area Configuration
for Services and Connections page,
expand Database Engine, click
Service, click Stop, wait until the
MSSQLSERVER service stops, and then
click Start to restart the
MSSQLSERVER service.