We all use them. But confess rarely need to change the seed on an identity colum in SQL server. Or if I do, it's probably going to happen via dropping and recreating the table. But once in a while it's handy to be able to change the seed.
How do I... Reseed a SQL Server identity column?
DBCC CHECKIDENT
(
tablename
[, [NORESEED | RESEED [, newreseedvalue]]]
)Is something I'm tucking away in my goody bag for another day.
| | |
|
Every so often I experience problems importing data from Office files (usually XLS) into SQL. Sometimes everything works fine, others not. I've always suspected it's because I don't actually have Office installed on my Windows part of my Mac, although I do have SQL, SQL Express, and an old copy of Access.
This morning I was importing an XLS with a couple of thousand lines, into SQL 2008. And up popped this message:
The microsoft.ace.oledb.12.0 provider is not registered on the local machine
A quick Google and I found this forum which leads to this Microsoft download page for the 2007 Office System Driver: Data Connectivity Components. I downloaded and installed and now SQL likes my XLS file.
| | |
|
Following on from my post yesterday 'Calculate distance between web site visitor IP and list of locations' I've come across an interesting revelation.
The client was off playing with my new page that establishes the web site visitor's geolocation from their IP number. And he complained because nothing was right.
Turns out he was browsing the page via iPhone. So I set up a test with my own iPhone, and hey presto, the IP geolocator system database thinks my phone is in Sydney. Which is definitely incorrect because it's sitting on my desk in front of me here in Melbourne. I proved the point by switching the iPhone's wifi back on, and now it correctly reports its location as Melbourne.
What I presume is that mobile carriers assign IP numbers to mobile devices from a central place - eg the IP range is probably designated to their head office or datacentre. And thus, like me, your phone can think it's in Sydney when in reality it's in Melbourne.
Of course iPhone Apps can access a phone's coordinates in a different way via the cellular network - hence some applications popping up a message asking you to agree to them accessing your location. That's how cool gadgets like Four Square work.
But it you rely on IP/coordinate lookups then the answer will be wrong.
For the moment I think we'll disable the fancy stuff on the web site for people browsing with mobile devices, but now I'm wondering how we can deal with this revelation.
| | |
|
ISAPI ReWrite has been driving me up the wall for the last day or two. I have Version 3 (fully registered) installed on a web server, which has half a dozen individual web sites up and running. I wanted to implement some rewrite rules for one of the web sites, so I used the ISAPI ReWrite Manager interface to edit the .htaccess file in the root of that specific web site and add a rule along the lines of:
RewriteRule /register/([^/]+)/ /register/register.asp\?eventId=$1 [I,L]
I already have this web site running on my development server, and I know this rule works.
The rules didn't work. I moved them up to the top level of the Manager, which edits the httpd.conf file in the installation directory for ISAPI ReWrite. And the rules worked.
I turned on logging by adding this to the httpd.conf file:
#enabling rewrite.log
RewriteLogLevel 9
#enabling error.log
LogLevel debug
The logging clearly showed the .htaccess file being accessed and the rules in that file being run through:
Htaccess process request d:\inetpub\wwwroot\mydomain.com\.htaccess
applying pattern '/register/([^/]+)/' to uri 'register/My-Event-Name/'
But no dice in the browser, just file not found errors. So the rule is being processed, but the resulting URL clearly is not right.
I read through the troubleshooting information on the Helicon web site. Which is when this phrase caught my eye:
Also remember that rewriting base inside .htaccess files by default is different from httpd.conf. ISAPI_Rewrite automatically strips the local directory prefix from the path when in .htaccess or <Directory> section and applies rules only to the remainder. So if your rules start with a '/' character, this should be removed in .htaccess file in the root folder of web site.
This is the first time I've used the registered version of ISAPI ReWrite, in the past I've only used the Lite version, mostly because I didn't need to bring rules down to the level of the individual web site (on this project I will need to because multiple sites will need the same URL/folder combinations).
So the idea that there is a subtle but key difference in the way you construct the rewrite rules between .htaccess at the individual site level, and the top level httpd.conf file has never come across my radar before.
I amended the rule to:
RewriteRule register/([^/]+)/ /register/register.asp\?eventId=$1 [I,L]
Notice there is no forward slash in front of the register/ name. And the redirect worked completely fine.
| | |
|
If you see an error like the following in your web code and SQL Server, what do you naturally think is the problem:
Microsoft Cursor Engine error '80040e21'
Multiple-step operation generated errors. Check each status value.
Well, looks like a database error, given the 'cursor engine' phrase. But a 'multi-step operation'?
I've now discovered that it appears almost always to be you trying to insert a string that's too long for the field.
I love descriptive, intuitive error messages.
| | |
|
I've been helping set up a new web site, we have two servers, all very off the shelf, both running Windows Server 2008, one with SQL Server 2008 as the database sever, the other acting as the web server.
The two boxes sit behind a firewall with only the necessary ports open (eg 80, 21, 443 etc). Windows FIrewall is turned on for both boxes, and on the SQL box we have port 1433 open but restricted to only the internal IP of the web server, so the web application can connect to the database.
The application is talking to the database using a standard connection string along the lines of:
Provider=sqloledb; Network Library=DBMSSOCN; Data Source=[sql server ip]; Initial Catalog=[db name]; User ID=[db user]; Password=[password];
We loaded up the site without major problems, but then started to notice this error occuring at seemingly random moments:
Microsoft OLE DB Provider for SQL Server error '80004005'
Login timeout expired
There seemed no rhyme nor reason, one minute you are browsing pages, the next up pops this error, then you refresh the page and all was well.
Clearly it's a connection error between the web application and the SQL server. I dug into the Windows and SQL logs everywhere trying to correlate entries with the time the error occured, but to no avail.
There's a fair amount online about this error, although it's often tied to simple connectivity issues, such as incorrect IP numbers, server address, firewall settings and the like.
Finally I stumbled over this page 'Troubleshooting: Timeout Expired' which gave the clue, and particularly:
'Either start the SQL Server Browser service, or connect specifying the TCP/IP port number.'
We don't have the SQL Server Browser service running - it's not started by default. So I simply added the port number to the connection string and, fingers crossed, everything's been fine since, eg:
Provider=sqloledb; Network Library=DBMSSOCN; Data Source=[sql server ip],[ip]; Initial Catalog=[db name]; User ID=[db user]; Password=[password];
Actually I normally DO have the port number in the connection string - because I fell into the habit for a long time of running SQL on a non-standard port to avoid nasties with 1433 worms and the like in situations where I wasn't so confident about the firewalling, or where we needed to leave the SQL Server exposed with IP or tunnel protection.
| | |
|
I have a Windows Server 2003 box with a bunch of scheduled tasks that fire VBS scripts through the day, handling various maintenance, data import and other jobs for a client's web site.
Over the past few days I noticed the jobs were not firing, and after a fair bit of research I finally found a solution.
The first clue came when I tried to call the VBS scripts directly in the command prompt, and received the following error message:
cscript error loading your settings failed access is denied
Which seemed a strange error given I was logged in as a user with Administrator permissions.
After a little more poking around I noticed two more oddities:
1. The Start Menu didn't look right - for example, the Accessories folder didn't contain many of the shortcuts I'd grown used to
2. The Documents and Settings folder contained duplicate user profile folders, for example:
- [username]
- [username].[machinename]
- [username].[machinename].000
- [username].[machinename].001
- [username].[machinename].002
all the way through to
- [username].[machinename].012
I also noticed in my command prompt window that I appeared to be logged in under the '012' profile.
I found this article that pointed the way:
http://support.microsoft.com/?kbid=314045
I searched the Registry for the ProfileImagePath key and found it was set to:
%SystemDrive%\Documents and Settings\[username].[machinename].002
I changed it to:
%SystemDrive%\Documents and Settings\[username]
I logged off, and logged back on again, and this time I was logged in with the [username].[machinename] profile - confirmed by opening the command prompt:
C:\Douments and Settings \[username].[machinename]>
I then tried to call the VBS scripts in the command prompt and they worked fine. Then via Scheduled Jobs window. Again all ok. And my Start Menu is back to normal as well.
As a sidebar I've noticed that the duplicate user profile folders were all created over the space of a single day - Christmas Day. Which is strange because I know that on Xmas Day I wasn't hunched over a computer RDCing into web servers, rather I was enjoying a day off with my family. The duplicate folders were all empty (eg they didn't have the normal complement of folders such as My Documents, Desktop, Favourites and so forth). All except the last one, 012. But that was the one I was logged into. So somehow Windows reacted to something and created the duplicates - but presumably whatever the 'something' was didn't constitute a login otherwise it would have populated the folders with the subfolders needed for the profile.
I've Google a little but can't immediately find anything that explains a big bunch of duplicate user profile folders turning up that are all empty.
All a bit strange, and I wish I had a more concrete explanation for how this all came about.
| | |
|
Here's an easy, blatant example of a web site with a built in problem, that the owner acknowledges but who has decided to make it the user's problem.
I picked up a parking ticket the other day and just went to pay the fine. It was with the City of Port Phillip, which like a bunch of councils around Melbourne uses the maxi.com.au online payment system (I remember Maxi launching years ago amidst much hullabaloo, ideas like terminals all over the city etc etc. Nowadays it still exists but only for these small irritating payments).
Anyhow, I dutifully pumped my Visa card number in, and back came the receipt page, which is a classic fail. Here's the page:
The text I've highlighted says:
(If you print your receipt, check the page set up on your browser to make sure it prints text as black.)
So of course, red rag to a bull, I clicked the print button, yup, an entire page of dark blue background plus the white text.
They KNOW it's a problem, but they put it onto the user to solve the problem. Hands up everyone who knows how to change the page set up on their browser so that it would reverse or otherwise deal with this ludicrous situation? I do this for a living and I'd probably fiddle for 5 minutes.
Yet the issue is so incredibly simple to fix - just change the styling on the page to a white background and dark text. In fact, I'm positive the last time I used Maxi this issue didn't exist - which means they've updated the site and created a new problem.
| | |
|
This has bugged me for a long time. I run Parallels on my MacBook Pro because I often have to work with Windows programming technologies, mostly Visual Studio and SQL Server. When I'm developing in Windows I run a localhost copy of the web site in IIS7 (I have Vista on my Mac). Up until now I've kept the site files in the Parallels VM windows drive, but this has constantly annoyed me because I don't back up my Windows drive with Time Capsule. Take too long and causes a marked slow down in my system each hour when the backup is running. Parallels has a specific option to not back up the VM with Time Capsule and I have that selected.
Every time I've ever tried to hook an IIS web site to a folder on my Mac (eg not in the VM) it's never worked - endless errors. Finally after a bit of hunting around I pulled together various tidbits of information from the net and made it work. Here's how:
1. In Parallels configuration make sure you are using Bridged Networking, this is to ensure your VM has a separate IP number to your Mac.
2. In Mac System Preferences > Sharing, enable File Sharing. Add the root folder for your web site (on your Mac) to the list of Shared Folders and give all users all rights (I kept it simple with permissions and just gave everyone every right, it's only for my localhost so I don't think security is a big deal).
3. In Windows use File Explorer and open Network and locate your Mac and the root folder for your web site. Copy the path, on mine it looks like \\MACBOOKPRO-31F6\wwwroot
4. In Windows IIS add a new web site, In Advanced Settings set the Physical Path to the network path you copied above
5. Still in Advanced Settings set the Physical Path Credentials to your Mac user name and password. I wound up adding a new Windows user with the same user name and password as I have on the Mac. I'm not completely sure if this is the right thing to do, but heck, it worked.
6. If you already have a default web site in IIS, you'll need to sort out the bindings, you can't have more than one web site on the same port, which by default is 80. Right click the new web site and edit the Bindings. I set the port to 8080.
7. In Windows open your browser and try http://localhost:8080/, you should see the default page, if you have one, from the folder on your Mac. If, like me, it didn't work first time, try creating a simple hello.htm and calling that. I discovered my problem was simply paths and configuration variables in my web site - moral being try calling the most basic page first before blaming errors on IIS rather than your web app.
| | |
|
ASP: Hiding file locations by binary stream reading
I do a lot of work with internet content business - companies that earn their living by managing documents and content, either for their own services or on behalf of customers.
Often this involves making documents on the server available for viewing, but without propagating the URL of the actual file, and with permission checks to ensure that the person viewing the file is authorised to do so.
Here's a simple technique to make a file, such as a PDF, available without revealing the file's URL and with a security check.
The trick is to binary read the file to the user's browser, instead of the user opening the file directly. In ASP we do this with the ADODB.Stream object. This allows us to open the file on the web server as a binary stream and send it to the browser. The user will be none the wiser to the file's location.
' Run a security check
' Add code here to ensure that the logged in user has permission to view the file
' if we have a file identifier
if fileId>0 then
' grab the file's name and location - probably from a database table
sqlStr="SELECT filePath,fileName FROM tblMyFiles WHERE fileId="&request("fileId")
set rs=Server.CreateObject("adodb.Recordset")
rs.cursorlocation=aduseclient
rs.cachesize=1
rs.open sqlStr, conn, adOpenForwardOnly,adLockReadOnly
' if the file entry in our database table is found
if not rs.eof then
' open the file system object
Set objFSO = Server.CreateObject("Scripting.FileSystemObject")
' check the file we want does actually exist
If objFSO.FileExists(filePath&lcase(rs("fileName"))) then
' and if it does exist, then spit out to the browser
' open a binary stream for the file
Set strOutStream = Server.CreateObject( "ADODB.Stream" )
strOutStream.Type = 1 'adTypeBinary
strOutStream.Mode = 3 'adModeReadWrite
strOutStream.Open
' load the file into the stream
strOutStream.LoadFromFile (filePath&lcase(rs("fileName")))
Response.Buffer = TRUE
' use the content type appropriate to the file - here we're using a PDF
Response.ContentType = "application/pdf"
Response.AddHeader "content-disposition", "inline; filename=" & rs("fileName")
Response.BinaryWrite (strOutStream.Read)
Response.End
strOutStream.Close
Set strOutStream = Nothing
end if
set objFSO=nothing
end if
rs.close
Set rs=nothing
end if
| | |
|
