2008年5月21日

[Info]Enterprise Library 4.0發佈了

NewpnpheroA

The patterns & practices Enterprise Library is a collection of application blocks designed to assist developers with common enterprise development challenges. Application blocks are a type of guidance, provided as source code that can be used "as is," extended, or modified by developers to use on enterprise development projects.

Enterprise Library 4.0是For Visual Studio 2008的版本。

你可以到這裡下載。

如果你在使用上有遇到一些問題,或是想找一些sample code以及教學,可以到codeplex討論群組找看看有沒有解決方法 - http://www.codeplex.com/entlib

[Info]Silverlight 2.0 教學網站

silverlight_learn

一個Silverlight教學的網站,內容很豐富。提供的是Step By Step的教學,可以邊看邊學,讚!!

有興趣的朋友可以去看看

http://www.miketaulty.com/SLVideos.html

2008年5月6日

如何檢查SQL Server連線問題?

今天在MSDN Blog上看到這篇列出檢查步驟的文章,節錄部分內容跟大家分享一下。

連線不通的原因

Basically, when you failed to connect to your SQL Server, the issue could be:

1) Network issue,

2) SQL Server configuration issue.

3) Firewall issue,

4) Client driver issue,

5) Application configuration issue.

6) Authentication and logon issue.

檢查步驟;

Step 1: Network issue

ping -a <your_target_machine>

(use -4 and -6 for IPv4 and IPv6 specifically)

ping -a <Your_remote_IPAddress>

nslookup (type your local and remote machine name and IP address multiple times)

If you are not able to ping your target machine, it has high chance that either the network is broken or the target machine is not running. It's possible the target machine is behind a firewall and the firewall blocks the packets sent by ping, though. Windows firewall does not block ping (ECHO) packet by default. The correctness of DNS configuration on the network is vital to SQL connection. Wrong DNS entry could cause of all sorts of connectivity issue later. See this link for example, "Cannot Generate SSPI Context" error message, Poisoned DNS.

Step 2: SQL Server configuration issue

You need to make sure the target SQL Server is running and is listening on appropriate protocols. You can use SQL Server Configuration Manager (SCM) to enable protocols on the server machine. SQL Server supports Shared Memory, Named Pipes, and TCP protocols (and VIA which needs special hardware and is rarely used). For remote connection, NP and/or TCP protocols must be enabled. Once you enabled protocols in SCM, please make sure restart the SQL Server.

You can open errorlog file to see if the server is successfully listening on any of the protocol. The location of errorlog file is usually under:

%ProgramFile%Microsoft SQL Server/MSSQLxx.xxx/MSSQL/Log

If the target SQL instance is a named instance, you also need to make sure SQL Browser is running on the target machine. If you are not able to access the remote SQL Server, please ask your admin to make sure all these happen.

Step 3: Firewall issue

A firewall on the SQL Server machine (or anywhere between client and server) could block SQL connection request. An easy way to isolate if this is a firewall issue is to turn off firewall for a short time if you can. Long term solution is to put exception for SQL Server and SQL Browser.

For NP protocol, please make sure file sharing is in firewall exception list. Both file sharing and NP use SMB protocol underneath.

For TCP protocol, you need put the TCP port on which the SQL Server listens on into exception.

For SQL Browser, please put UDP port 1434 into exception.

Meanwhile, you can put sqlservr.exe and sqlbrowser.exe into exception as well, but this is not recommended. IPSec between machines that we are not trusted could also block some packets. Note that firewall should never be an issue for local connections.

Step 4: Client driver issue

First try:

telnet <your_target_machine> <TCP_Port>

You should be able to telnet to the SQL server TCP port if TCP is enabled. Otherwise, go back to check steps 1-3. Then, use OSQL, SQLCMD, and SQL Management Studio to test sql connections. If you don't have those tools, please download SQL Express from Microsoft and you can get those tools for free.

Possilbe command use be:

osql -E -SYour_target_machine\Your_instance for Windows Auth

osql -Uyour_user -SYour_target_machine\Your_instance for SQL Auth

SQLCMD also applies here. In addition, you can use <“-Stcp:Your_target_machine, Tcp_port” for TCP, “-Snp:Your_target_machine\Your_instance” for NP, and “-Slpc:Your_target_machine\Your_instance” for Shared Memory. You would know if it fails for all protocols or just some specific procotols.

At this stage, you should not see general error message such as error 26 and error 40 anymore. If you are using NP and you still see error 40 (Named Pipes Provider: Could not open a connection to SQL Server), please try the following steps:

a) Open a file share on your server machine.

b) Run “net view file://your_target_machine/” and “net use file://your_target_machine/your_share” (You can try Map Network Drive from Windows Explorer as well)

If you get failure in b), it's very likely you have OS/Network configuration issue, which is not SQL Server specific. Please search on internet to resolve this issue first.

You can try connection using both Windows Authentication and SQL Authentication. If the tests with all tools failed, there is a good chance that steps 1-3 were not set correctly, unless the failure is logon-related then you can look at step 6.

If you succeeds with some of the tools, but fails with other tools, it's probably a driver issue. You can post a question on our forum and give us the details.

You can also use “\windows\system32\odbcad32.exe” (which ships with Windows) to test connection by adding new DSN for various drivers, but that's for ODBC only.

Step 5: Application issue

If you succeed with steps 1-4 but still see failure in your application, it's likely a configuration issue in your application. Think about couple of possible issues here.

a) Is your application running under the same account with the account you did tests in step 4? If not, you might want to try testing in step 4 under that account or change to a workable service account for your application if possible.

b) Which SQL driver does your app use?

c) What's your connection string? Is the connection string compatible to your driver? Please check http://www.connectionstrings.com/ for reference.

Step 6: Authentication and logon issue

This is probably the most difficult part for sql connectivity issues. It's often related to the configuration on your network, your OS and your SQL Server database. There is no simple solution for this, and we have to solve it case by case. There are already several blogs in sql_protocols talking about some special cases and you can check them see if any of them applies to your case. Apart from that, things to keep in mind:

a) If you use SQL auth, mixed authentication must be enabled. Check this page for reference http://msdn.microsoft.com/en-us/library/ms188670.aspx

b) Make sure your login account has access permission on the database you used during login ("Initial Catalog" in OLEDB).

c) Check the eventlog on your system see if there is more information

reference from:

http://blogs.msdn.com/sql_protocols/archive/2008/04/30/steps-to-troubleshoot-connectivity-issues.aspx

[Info] 如何快速找到Fix it?

  台灣微軟目前提供了很多的Fix it,讓許多消費者可以不用看完整篇KB,只要按下一個按鈕,就可以幫使用者自動修正許多問題. 現在在Vista以及Windows 7上,微軟也提供了SideBar工具,讓你用最短的時間找到能修正您的電腦的Fix it.(目前為英文版本) ...