Error: 40- could not open a connection to SQL Server - in Visual Studio 2019

Question

Error: 40- could not open a connection to SQL Server - in Visual Studio 2019

daowdos 296

Hello everyone,
I can't connect to SQL Server inside Visual Studio 2019.
The Microsoft SQL by itself is connecting, its only inside visual studio.

I get error 40. I followed the steps and restart SQL in "Services" but that didn't help.

What can I do to solve this ?

Thanks in advanced.

Error: 40- could not open a connection to SQL Server - in visual studio 2019

Karen Payne MVP 35,586 Reputation points Volunteer Moderator

2021-07-28T15:27:47.313+00:00

See the following which provides diagnostic steps to follow
daowdos 296 Reputation points

2021-07-28T15:38:39.03+00:00

It's too old, nothing is like that in windows today.
its very different and I cant go through those steps, sorry.
Not solving my problem.

Karen Payne MVP 35,586 Volunteer Moderator

Perhaps running the following PowerShell script might help

$SqlConnection = New-Object System.Data.SqlClient.SqlConnection  
$SqlConnection.ConnectionString = "Data Source=.\SQLEXPRESS;Initial Catalog=master;Integrated Security=True"   
$SqlCmd = New-Object System.Data.SqlClient.SqlCommand  
$SqlCmd.CommandText = 'SELECT @@SERVERNAME AS ServerName'  
$SqlCmd.Connection = $SqlConnection   
$SqlConnection.Open()  
$rdr = $SqlCmd.ExecuteReader()  
while($rdr.Read())  
{  
  $rdr["ServerName"].ToString()  
}  
$SqlConnection.Close()

daowdos 296 Reputation points

2021-07-28T16:03:38.217+00:00

Hi Karen,
I ran all the commands in the PowerShell but the same problem.

I I don't understand what this code for
and why

$SqlConnection.Close()

is closed it at the end ?
AgaveJoe 30,126 Reputation points

2021-07-28T16:26:19.217+00:00

The error usually indicates an error entering the server\instance; (localdb)\MSSQLLocalDB. If you are trying to connect to the local db then a dot or (local) will work.

VS 2019 has a feature named "SQL Serer Object Explorer" (under the View menu) which enumerates the SQL instance found on the local machine.

Select the instance you are trying to connect and configure the authentication according to your configuration.
daowdos 296 Reputation points

2021-07-28T16:40:53.917+00:00

My SQL Server's database is shown there, but I still can't connect it with Server Explorer - same error as before.
Karen Payne MVP 35,586 Reputation points Volunteer Moderator

2021-07-28T16:46:49.703+00:00

Yes it closes the connection.

Accepted answer

0 additional answers

Your answer

Karen Payne MVP 35,586 Reputation points Volunteer Moderator

2021-07-28T15:27:47.313+00:00

See the following which provides diagnostic steps to follow
daowdos 296 Reputation points

2021-07-28T15:38:39.03+00:00

It's too old, nothing is like that in windows today.
its very different and I cant go through those steps, sorry.
Not solving my problem.
Karen Payne MVP 35,586 Reputation points Volunteer Moderator

2021-07-28T15:55:53.317+00:00

Perhaps running the following PowerShell script might help

$SqlConnection = New-Object System.Data.SqlClient.SqlConnection $SqlConnection.ConnectionString = "Data Source=.\SQLEXPRESS;Initial Catalog=master;Integrated Security=True" $SqlCmd = New-Object System.Data.SqlClient.SqlCommand $SqlCmd.CommandText = 'SELECT @@SERVERNAME AS ServerName' $SqlCmd.Connection = $SqlConnection $SqlConnection.Open() $rdr = $SqlCmd.ExecuteReader() while($rdr.Read()) { $rdr["ServerName"].ToString() } $SqlConnection.Close()
daowdos 296 Reputation points

2021-07-28T16:03:38.217+00:00

Hi Karen,
I ran all the commands in the PowerShell but the same problem.

I I don't understand what this code for
and why

$SqlConnection.Close()

is closed it at the end ?
AgaveJoe 30,126 Reputation points

2021-07-28T16:26:19.217+00:00

The error usually indicates an error entering the server\instance; (localdb)\MSSQLLocalDB. If you are trying to connect to the local db then a dot or (local) will work.

VS 2019 has a feature named "SQL Serer Object Explorer" (under the View menu) which enumerates the SQL instance found on the local machine.

Select the instance you are trying to connect and configure the authentication according to your configuration.
daowdos 296 Reputation points

2021-07-28T16:40:53.917+00:00

My SQL Server's database is shown there, but I still can't connect it with Server Explorer - same error as before.
Karen Payne MVP 35,586 Reputation points Volunteer Moderator

2021-07-28T16:46:49.703+00:00

Yes it closes the connection.

Answer 1

Tom Phillips 17,771

That error is a generic "could not connect to server" message and does not help in any way diagnose the actual problem.

What exactly did you enter for the server name? Try "./sqlexpress", since your screen shot appears you have installed an instance named "sqlexpress".

I suggest you start here:
https://learn.microsoft.com/en-us/sql/database-engine/configure-windows/troubleshoot-connecting-to-the-sql-server-database-engine?view=sql-server-ver15#testing-a-local-connection

daowdos 296 Reputation points

2021-07-28T16:45:11.17+00:00

Thank you, you helped me.

I needed to add my server name, I thought it need to be added automatically.
Forgot about that, silly me.

Elad

Share via

Error: 40- could not open a connection to SQL Server - in Visual Studio 2019

0 additional answers

Your answer