Connecting programmatically or by using osql<\/tt> failed with the following, generic error:<\/p>\n error: 40 - Could not open a connection to SQL Server<\/tt><\/p><\/blockquote>\n My programmatic attempt looked like this:<\/p>\n Other variants I tried for Data Source<\/tt> were (local)<\/tt>, 127.0.0.1<\/tt>, and the fully-qualified name of my local server.<\/p>\n My osql<\/tt> attempt looked like this:<\/p>\n The solution, at least for the basic connection problem, turned out to be a missing instance name. The instance name can be found by looking in Programs | Microsoft SQL Server 2005 | Configuration Tools | SQL Server Configuration Manager, under SQL Server 2005 Services. In my case, the instance is named “SQLEXPRESS<\/tt>“, so I tacked this onto my connection strings for a (more) successful login.<\/p>\n Programmatic:<\/p>\n osql<\/tt>:<\/p>\n Actually, the above code didn’t quite work. I still get an authorization error:<\/p>\n This was actually because I hadn’t yet created the database, nor a user! I followed this handy guide<\/a> in order to create a database, a user, and grant the user access to the new database.<\/p>\n In the end, my connection code looks like this:<\/p>\n Problem Connecting programmatically or by using osql failed with the following, generic error: error: 40 – Could not open a connection to SQL Server My programmatic attempt looked like this: string cs = “Data Source=localhost;” + “Trusted_Connection=true;” + “Initial Catalog=dbname;”; … Continue reading \n
string cs = \"Data Source=localhost;\" +\r\n \"Trusted_Connection=true;\" +\r\n \"Initial Catalog=dbname;\";\r\nSqlConnection connection = new SqlConnection(cs); \r\nconnection.Open();<\/pre>\n<\/blockquote>\n
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c:\\>osql -E -S localhost<\/pre>\n<\/blockquote>\n
Solution<\/h3>\n
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string cs = \"Data Source=localhost\\\\sqlexpress;\" +\r\n \"Trusted_Connection=true;\" +\r\n \"Initial Catalog=dbname;\";\r\nSqlConnection connection = new SqlConnection(cs);\r\nconnection.Open();<\/pre>\n<\/blockquote>\n
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c:\\>osql -E -S localhost\\sqlexpress\r\n1> <\/pre>\n<\/blockquote>\n
Authorization<\/h3>\n
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Cannot open database \"dbname\" requested by the login. The login failed.\r\nLogin failed for user 'DOMAIN\\username'.<\/pre>\n<\/blockquote>\n
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string cs = \"Data Source=localhost\\\\sqlexpress;\" +\r\n \"Trusted_Connection=true\" +\r\n \"Initial Catalog=dbname;\" +\r\n \"user id=username;password=userpass;\";\r\nSqlConnection connection = new SqlConnection(cs);\r\nconnection.Open();<\/pre>\n<\/blockquote>\n","protected":false},"excerpt":{"rendered":"