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Old August 23rd, 2006, 12:24 PM
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Default SQL Server open problem

I purchased the book “Professional C# 2nd Edition” by Robinson, Allen, etc. (2002) and am not able to run any of the examples that use SQL Server. For example, the executable ‘DataAccess\01_ExecutingCommands\ ExecutingCommands.exe’ generates an exeception when function SqlConnection.open()is run. The abbreviated error message is:

System.Data.SqlClient.SqlException: An error has occurred while establishing a c onnection to the server. When connecting to SQL Server 2005, this failure may b e caused by the fact that under the default settings SQL Server does not allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server) at System.Data.SqlClient.SqlConnection.Open() at ExecutingCommands.ExecuteSql(String source) in \C#, 2nd edition\DataAccess\01_ExecutingCommands\ExecutingC ommands.cs:line 48

Can the examples provided in the test book be run as is or is it necessary to somehow initialize the database files (e.g. C:\Program Files\Microsoft Visual Studio 8\SDK\v2.0\Samples\Setup\ InstNwnd.sql)first?

MS VS NET 2005 and SQL Server (32 bit version) are installed on my computer which is running Win XP Pro.

Old August 24th, 2006, 03:35 AM
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First of all: by default your SQL server and C# Application must be on 1 computer.

try it:
string connectionString = "user id=ANY_user;password=ANY_PASS;server=YOUR_COMP_NAM E\\SQLEXPRESS;Trusted_Connection=yes; database=MySqlTestDb; connection timeout=30";
SqlConnection myConnection = new SqlConnection(connectionString );
connection string:
The User ID is used when you are using SQL Authentication, but here this is ignored, because of using Trusted_Connection.
MySqlTestDb - such database must exist in folder
"C:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\Data\MySqlTestDb.mdf"
you can create it with "Server Explorer" utility in Visual Studio or use some standart db

Old August 24th, 2006, 05:19 PM
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Thanks for the suggestion but it produces a similar error message.
I have included the full error message here. In addition, I have added the sample code that generates this message. Please note the database file you recommended is not found in the specified directory. However, the NorthWind database was and this is what I attempted to read. This database file was copied to the directory containing the C# source code.

Thank you for any comments and/or suggestions.

Error message:

System.Data.SqlClient.SqlException: Cannot open database "northwnd" requested by
 the login. The login failed.
Login failed for user 'DA3\Ian Bell'.
   at System.Data.SqlClient.SqlInternalConnection.OnErro r(SqlException exception
, Boolean breakConnection)
   at System.Data.SqlClient.TdsParser.ThrowExceptionAndW arning(TdsParserStateObj
ect stateObj)
   at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cm
dHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, Tds
ParserStateObject stateObj)
   at System.Data.SqlClient.SqlInternalConnectionTds.Com pleteLogin(Boolean enlis
   at System.Data.SqlClient.SqlInternalConnectionTds.Ope nLoginEnlist(SqlConnecti
on owningObject, SqlConnectionString connectionOptions, String newPassword, Bool
ean redirectedUserInstance)
   at System.Data.SqlClient.SqlInternalConnectionTds..ct or(DbConnectionPoolIdent
ity identity, SqlConnectionString connectionOptions, Object providerInfo, String
 newPassword, SqlConnection owningObject, Boolean redirectedUserInstance)
   at System.Data.SqlClient.SqlConnectionFactory.CreateC onnection(DbConnectionOp
tions options, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection
   at System.Data.ProviderBase.DbConnectionFactory.Creat ePooledConnection(DbConn
ection owningConnection, DbConnectionPool pool, DbConnectionOptions options)
   at System.Data.ProviderBase.DbConnectionPool.CreateOb ject(DbConnection owning
   at System.Data.ProviderBase.DbConnectionPool.UserCrea teRequest(DbConnection o
   at System.Data.ProviderBase.DbConnectionPool.GetConne ction(DbConnection ownin
   at System.Data.ProviderBase.DbConnectionFactory.GetCo nnection(DbConnection ow
   at System.Data.ProviderBase.DbConnectionClosed.OpenCo nnection(DbConnection ou
terConnection, DbConnectionFactory connectionFactory)
   at System.Data.SqlClient.SqlConnection.Open()
   at ExecutingCommands.ExecuteSql(String source) in C:\Documents and Settings\I
an Bell\My Documents\temp\testCSConsoleApplication\testCSCons oleApplication\Exec
utingCommands.cs:line 37

Sample Code:

using System;
using System.Data;
using System.Xml;
using System.Data.SqlClient;
using System.Data.OleDb;

/// <summary>
/// Corresponds to section titled 'Executing Commands' in Chapter 11
/// </summary>
public class ExecutingCommands
    /// <summary>
    /// SimpleDataAccess - show SQL & Stored Procs
    /// </summary>
    public static void Main ( )
        string source = "user id=ANY_user;password=ANY_PASS;server=da3\\SQLEXPRE SS;Trusted_Connection=yes; database=northwnd; connection timeout=30";
                // The following is the database connection string
        //string source = "data source=(local);initial catalog=Northwind;integrated security=SSPI;";

        // First section of code - using a SQL statement to select records
        ExecuteSql ( source ) ;


    public static void ExecuteSql ( string source )
        // And this is the SQL statement that will be issued
        string select = "SELECT ContactName,CompanyName FROM Customers";

            // Connect to the database...
            using ( SqlConnection conn=new SqlConnection(source) )
                // Open the database connection
                conn.Open ( ) ;

                // Create the SQL command...
                SqlCommand cmd = new SqlCommand ( select , conn ) ;

                // Construct the data reader
                using ( SqlDataReader reader = cmd.ExecuteReader ( ) )
                    // Output headings...
                    Console.WriteLine ( "*** SqlProvider ***" ) ;
                    Console.WriteLine ( "Output from direct SQL statement..." ) ;
                    Console.WriteLine ( ) ;
                    Console.WriteLine ( "CONTACT COMPANY" ) ;
                    Console.WriteLine ( "---------------------------------------------------------------------" ) ;

                    // And iterate through the data
                    while ( reader.Read ( ) )
                        Console.WriteLine ( "{0,-30} {1}" , reader[0] , reader[1] ) ;

                    reader.Close ( ) ;

                conn.Close ( ) ;
        catch ( Exception e )
            Console.WriteLine ( e.ToString( ) ) ;

Old August 25th, 2006, 03:50 AM
2V. 2V. is offline
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Hey, Are you shure that your database "northwnd" exist ???
Ok, try next: In MVS 2005 Menu choose View - Server Explorer. than - data Connection - <right click> Add connection... SQL Server.. Continue.. "Server Name" (compname\servname) - Choose available server name "Select or enter db" - Choose your db. Press button Test Connection ...
and one more thing: <SQL Server(SQLEXPRESS)> and <SQL Server Browser> - this services must be runned.

Old August 25th, 2006, 10:43 AM
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Hello Ukraine,

This still does not work and both the 'Northwind.mdb' and 'Northwind.mdf' files exists. I've just ordered a book that deals exclusively with programming data bases. I will wait until it arrives and hopefully it will contain sufficiently detailed information so that I can work through the examples.

Thanks again for your time and effort. It was good of you to trying helping me out.


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