Error: A network-related or instance-specific error occurred while establishing a connection to SQL Server.

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: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)

If you encounter above error, while running your VS.Net, than first thing you should do is to check your web.config file to make sure that connection string is correct.

This problem might occur if you have recently

• Change your PC Name
• Installed new sql server instance but have not updated your web.config file with correct instance name.

Example:
Earlier you were using instance name "YourPCName\SQLExpress" but due to new sql server instance installation your instance name changed to "YourPCName\CustomInstanceName".

Below is sample connection string, where text in red is cause of problem.
Data Source=MyPCName\MySQLInstance;Initial Catalog=MyDBName;Integrated Security=True


Solution
Check Connection string in your vs.net solutions, web.config file and correct with new sql server instance name.

Related Links - FullText Search Query Example

In any application generating related links is little challenging and it is very hard to get accurate result.  I have try to create example of related link query which will fetch close result of what you are looking for.

Consider an example of any website with article section and if you are trying to give related links using fulltext search query of sql server, than following query would be helpful.

If you are new to fulltext search and would like to understand more on how fulltext search works in sql server

Step 1: Check whether fulltext search is installed
Select SERVERPROPERTY('IsFullTextInstalled')
If this query returns a value of '1' then the component is installed.

Step 2: Create FullText Catalog

Create FullText Catalog MyDBNameCatalog

Step 3: Create FullText Index on Table

Create FullText Index on ArticlesTable

(ArticleTitle)

Key Index PK_ArticleTable_ArticleID on MyDBNameCatalog

with Change_Tracking Auto

Step 4: Creating Query - Example Query Related Links for Article in SQL Server

Select ftt.Rank, *

from ArticleTable

Inner Join FreeTextTable(ArticleTable, ArticleTitle, 'ISABOUT("My Search Text")') as ftt

on ftt.[Key] = ArticleTable.ArticleId

Order by ftt.Rank desc

Step 5: Now you are ready to create stored procedure which can return related links

GO

SET ANSI_NULLS ON

GO

SET QUOTED_IDENTIFIER ON

GO

Create PROCEDURE [dbo].[ArticleTable_ReleatedLinks_FullTextSearch]

@ArticleId bigint,

@ArticleTitle varchar(500),

@iErrorCode int OUTPUT

AS

SET NOCOUNT ON

set  @ArticleTitle = 'ISABOUT(' +  @ArticleTitle + ')'

SELECT Top 20

ArticleTable.[ArticleId],

ArticleTable.[ArticleTitle]

FROM ArticleTable

Inner Join FreeTextTable(ArticleTable, ArticleTitle, @ArticleTitle) as ftt

on ftt.[Key] = ArticleTable.ArticleId

Where

ArticleTable.ArticleId != @ArticleId

ArticleTable.IsDeleted = 0

Order by ftt.Rank desc

-- Get the Error Code for the statement just executed.

SELECT @iErrorCode=@@ERROR

To understand about how FreeTextTable query works and for more examples and syntax