SQL Server

activerecord and executereader exceptions

Alex Bransky — Wed, 28 May 2008 20:46:45 GMT

About once a day I was getting the following error from an ASP.Net web page that uses ActiveRecord:

Exception Details: System.Data.SqlClient.SqlException: A transport-level error has occurred when sending the request to the server. (provider: TCP Provider, error: 0 - An existing connection was forcibly closed by the remote host.)

I would subsequently get this error upon refreshing the page:

Exception Details: System.InvalidOperationException: ExecuteReader requires an open and available Connection. The connection's current state is closed.

I finally figured out that the problem occurs when the database is restored. The connections in the IIS application pool do not get destroyed when the database is restored, so when ActiveRecord (nHibernate) tries to reuse the connections it fails. This doesn't happen to me when I'm not using ActiveRecord, so I'm not sure if this is a bug with ActiveRecord or a problem with the way I've set up the data access layer.

ssas: define reference and materialize

Alex Bransky — Thu, 10 Apr 2008 22:25:34 GMT

Apparently you have to watch out when you select Materialize in a referenced dimension in SSAS 2005. I just ran into a situation where data was getting duplicated for no good reason, and unchecking Materialize fixed it.

http://www.biblogs.com/2006/12/23/materialize-option-in-a-reference-dimension/

granularity error in SSAS MDX drillthrough query

Alex Bransky — Wed, 09 Apr 2008 22:44:14 GMT

I was trying to create an MDX drillthrough this morning in my SSAS 2005 cube, and I got this error:

Errors from the SQL query module: The attribute 'Applicant Name' in the dimension 'Dim Candidate' is outside the granularity of the measure group 'Fact Requisitions' and cannot be returned as a column.

I only got one result from Google for that error message and it wasn't helpful at all. After trying a million different things with partitions and actions and whatnot, I finally figured out the problem: I was trying to return drillthrough data from a fact table other than the one containing the default measure. Once I threw in a measure (in the SELECT part of the query, not the RETURN) from the non-default fact table, everything worked great!

adding a fact table to a SSAS 2005 cube

Alex Bransky — Mon, 11 Feb 2008 21:28:08 GMT

So you're trying to add a fact table to a cube that you've already created, but you can't figure out how to do so without recreating the cube from scratch? Here's what you do: In the Measures pane in the Cube Structure tab, right-click and select New Measure Group. Then select the fact table, and voila! (This is assuming you've already put the fact table in the data source view.)

addendum: Looks like the standard way to add a dimension to the cube is to right-click on the cube name in the Dimensions window in the Cube Structure tab and select Add Cube Dimension.

SSAS cube: "attribute key not found" error

Alex Bransky — Wed, 06 Feb 2008 23:05:02 GMT

I just spent over an hour trying to figure out why my data tables were correct but I was getting an error about an attribute key not being found (i.e. an unlinkable foreign key). I finally figured out that processing one dimension at a time before processing the cube can get fix whatever is out of sync. [Right-click on the dimension in Solution Explorer to process it separately.]

SQL Server 2005 splash screen

Alex Bransky — Sat, 26 Jan 2008 00:38:06 GMT

Is the SQL Server 2005 splash screen supposed to look like Arkanoid or like Tetris?

fastest way to show SQL data in a web page

Alex Bransky — Wed, 21 Nov 2007 23:45:09 GMT

I'm curious what people think is that fastest way to show SQL Server data in a web page. Assuming you create the virtual web in IIS yourself, I'm hoping somebody knows of something that lets you create an xml file with connection settings and a query file, then the product automagically puts the data in a grid on the web page. Granted once you're used to Visual Studio it doesn't take terribly long to do such a thing, but I'd still like something faster, maybe something that can automagically create graphs too.

how do you handle huge databases?

Alex Bransky — Wed, 22 Aug 2007 16:55:53 GMT

I'm used to working with SQL Server databases that are somewhat small (10 GB or less, usually a lot less), so I'm curious how people deal with huge databases, like those that hold Amazon's transactions or whatever. Do you have to have the latest and greatest hardware running with clustered servers? Do you have to do a lot of database partitioning? How do you handle upgrades? Do you do then in the middle of the night so that you can take the db down briefly?

ALTER TABLE difference in SQL 2005

Alex Bransky — Tue, 07 Aug 2007 17:23:20 GMT

I think I may have found an undocumented difference between SQL Server 2000 and SQL Server 2005. When you attempt to add a non-null column without a default to an empty table in SQL Server 2000, for some stupid reason it won't let you if you use ALTER TABLE ADD [column]. You are forced to drop and recreate the table with the new column added to the CREATE TABLE statement. This appears to be different than SQL Server 2005, which wisely does allow such a command to execute without error. I haven't found documentation of this anywhere.

XML parsing error: An invalid character was found in text content.

Alex Bransky — Fri, 29 Jun 2007 23:26:15 GMT

So I was writing a script to pull out some old xml data, and I happened upon this error:

XML parsing error: An invalid character was found in text content.

It probably would have taken me centuries to figure out what character it didn't like, so I tried concatenating the following line to the front of the xml column in the SELECT statement I used to populate the cursor for openxml, and voila, no more error! I guess bumbles really do bounce.

'<?xml version=''1.0'' encoding=''iso-8859-1''?>'