Error:"A network-related or instance-specific error occurred while establishing a con"

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Hi I'm developing a VB.net application .. and when I try to connect to the databse I get this error; Itry many solution but nothing is working well with me ..Any Idea?

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)

Posted 5-Oct-12 7:21am

Lotus90

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Zoltán Zörgő 5-Oct-12 13:23pm

First of all, are you able to connect to the same database from the same computer using SQL Server Manager for example?

3 solutions

Solution 1

Probably, you have a problem with your connection string.
First off, try setting up a connection in VS with the Server Explorer pane:
1) Open Server Explorer.
2) Right click "Data connections" and select "Add connection"
3) In the dialog that follows, select your DataSource, and database, specify the security info, and press the "Test connection" button.
4) When the connection works, press "OK"
5) Highlight your database in the Server Explorer pane, and look at the Properties pane. A working example of the connection string will be shown, which you can copy and paste into your app or config file.

Your connection should now work.

Posted 5-Oct-12 8:03am

OriginalGriff

Solution 2

You havn't created a instance of SQL server (management studio),first complete your installation and then go for connection .if its their then, how you are making connection with Database ?can u post your code.so i can give you exact idea.:-)

Posted 5-Oct-12 8:05am

Mandi Kant

Updated 5-Oct-12 8:15am

v2

Comments

Lotus90 5-Oct-12 14:22pm

Imports System.Data.SqlClient
Imports System.Data
Dim con As New SqlConnection("Data Source=D:\Users\Reema\Documents\Test.sdf")
Dim cmd As SqlCommand
Dim dr As SqlDataAdapter
Private Sub Save_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Save.Click

If TextBox2.Text <> "" And TextBox3.Text <> "" Then

con.Open()
cmd.CommandText = "insert into test(id , name ) VALUES (' " & TextBox2.Text & " ','" & TextBox3.Text & " ')"
cmd.ExecuteNonQuery()
con.Close()

End If
End Sub

[no name] 5-Oct-12 14:31pm

Your connection string is all wrong.

Lotus90 5-Oct-12 15:22pm

Then what I have to do ?!

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Aarti Meswania · Accepted Answer · 2012-10-05T19:15:00

Solution 3

as per discussion in solution-2,
connection string is wrong.

sql connection string should be like below,

if sql server have Windows authentication Mode

"data source=ServerName; Initial Catalog=DatabaseName; Integrated security=true;"

if sql server have SQL authentication Mode

"data source=ServerName; Initial Catalog=DatabaseName; Uid=SQLServerLoginId;pwd=SQLServerPassword;"

Happy Coding!
:)

Posted 5-Oct-12 19:15pm

Aarti Meswania

Comments

Jithu Wilson C 11-Aug-16 7:43am

The same error happens after changing computer name. The above solution is not possible for me.

Dim cn As New SqlConnection("Data Source=JITHU-PC;Initial Catalog=vbsql;Integrated Security=True")
Firewall is OK
TCP/IP Port is OK.