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A client of mine has told me the program I made for them won't connect to a SQL server named instance, I have a standard SQL server with no named instance so I'm wondering how I can test this. A named instance connection string look like the one below, could the backslash be were my code fails?

Driver={SQL Native Client};Server=myServerName\theInstanceName;Database=myDataBase;

My code is as follows:

sqlServer=s.Substring(keyword.Length,s.Length-keyword.Length);
FormODBC formODBC=new FormODBC(this);
formODBC.SetSqlServer(sqlServer,dbUsername,dbPassword,database,table);
formODBC.ReadData();

How should I handle the backslash as I suspect this may be the problem?

Thanks

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6 Answers 6

Reset to default
5

Also, remember that backslash is an escape character in C# strings. If your instance name is contained in a string variable, make sure you do either:

string server = "myServer\\myInstance";

or

string server = @"myServer\myInstance";
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4

We have SQL servers with named instances. Examples: myservername\sql2005. Backslash is fine, in the conection string server name will be "myservername\sql2005", works 100% fine. You can have a "regular instance" on the same server, will be "myservername"

PS just unit test your function making connection string returns "myservername\sql2005".

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Thanks, I don't understand why but for me on my C# connection string "myservername\\InstanceName" was not working but "myservername\InstanceName" worked just fine.
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The answer is to ensure your connection string is configurable, and set it to something like:

data source=localhost\msexpress;database=dbname;trusted_connection=true;

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There is also the occassional SQL Express edition case where the name is MyServerName\SQLEXPRESS. This can trip up some people because they wouldn't think to specify the server that way.

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You can extract your connection string to a config file (note this isn't necessarily secure - that will depend on how their SQL security server is set up and the account your application is running under) - then your client can just add the appropriate connection string for their server to your application's config when deployed.

Notes:

  • You can create a connection string by renaming a .txt file to a .udl file and running through until you can connect to your/their server.
  • Your unamed instance can actually be accessed by name - the machine name on which the SQL server is installed
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Scott, At the risk of stating the obvious, have you tried setting up a named instance in your own development environment? I don't actually know the answer to your question but I've never personally run into a solution where testing the scenario that is failing directly didn't help. At a minimum you ought to be able to get better debugging information as to precisely what is failing. Good luck getting this resolved.

Regards, Chris

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3 Comments

If he is on a single machine and doesn't have a licence to run a named instance what then?
@Chris, I think he could have figured it out himself.
@flesh, he can install a free SQL Server Express as a named instance on his system. The whole world can use SQL Server Express for free. It is the same SQL Server engine as a paid licensed server, it just deals with a smaller amount of data (ie, less than 10 GB of total data).

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