COM woes – Retrieving COM class factory failed due to the following error: 80040154

COM woes – Retrieving COM class factory failed due to the following error: 80040154

I spent ages trying to figure out this problem, when trying to reference Microsoft Office Interop libraries in my project (For manipulating an Excel file programmatically).

Turns out, the dlls I was trying to reference were 32-bit, and the platform my project was set to run on was 64-bit. As I was building this project on a 64-bit machine, Visual Studio set the default platform to be 64-bit.

This is a simple fix: Go to the “Project” menu, select “Properties”, then click the “Build” tab on the side. From here you just need to select x86 from the Platform combo box and rebuild your project. Sorted!

http://forums.asp.net/t/1119052.aspx

Create SQL Table from .NET Datatable in C#

Create SQL Table from .NET Datatable in C#

In one of my recent projects I needed to generate a datatable in C# whose fields could vary depending on which properties of a variable needed to be exported from the system. It needed to be able to generate the SQL CREATE TABLE script on the fly and create the table in the database, and then populate the table with the data to export, either using a SqlBulkCopy object or on a row-by-row basis.

The tutorial below provides a good code base to developing this kind of functionality, as well as providing a link to a similar project on MSDN.

http://darrylagostinelli.com/2011/06/27/create-a-sql-table-from-a-datatable-in-c-net/

Dynamically Build SQL MERGE statement in SSIS

Dynamically Build SQL MERGE statement in SSIS

http://www.sqlservercentral.com/articles/EDW/77100/

I came across this the other day, when I was looking at using the SQL MERGE statement to replicate the functionality of the Slowly Changing Dimension task in SSIS. There are many benefits to using MERGE instead of the SSIS task, one of my favourites being only having to run 1 SQL statement for the whole task, instead of one for each Lookup, and then subsequent UPDATE or INSERT statement.

This link however, takes it one step further by dynamically building the MERGE statements to use in your ETL. This removes the need to manually update scripts when the table schema changes, such as adding new fields, and makes it a great candidate for quick deployment of Slowly Changing Dimension tasks.

Debugging MDX Queries from SSRS using Profiler and SQL Management Studio

Debugging MDX Queries from SSRS using Profiler and SQL Management Studio

At work recently I came across the need to assess the MDX queries used by some of the reports on our reporting server, along with the parameters that were passed into it (as most of the queries are powered by parameters that are passed into the MDX by parent reports)

Unfortunately, you can’t use SSMS to run parameterised MDX queries like you can in SSRS, but the tutorial below gives a good example using SQL Server Profiler, capturing traces of executed queries by SSRS along with the parameter values used. From here you can just paste the MDX into SSMS, replace the parameter names with the values used and presto!

http://prologika.com/CS/blogs/blog/archive/2009/07/06/how-to-test-ssrs-mdx-queries-in-sql-server-management-studio.aspx

Identifying cause of duplicate attribute keys in SSAS

Identifying cause of duplicate attribute keys in SSAS

http://ms-olap.blogspot.com/2009/11/duplicate-attribute-key-has-been-found.html

At work today, I was a bit stumped when SSAS reported the cube wouldn’t build, due to a duplicate key found in the source database, although having checked this there was none to be found.

However after consulting with a colleague, and finding this article on the internet, it turns out that there was a white space after the value of an attribute in the source DB. After SSAS runs the DISTINCT query on the source DB, it trims the white space, and because of that it created a duplicate key.

The post-processing of attributes can be customised in the dimension designer in SSAS. For me it was an issue with the source data, but possibly for you, it might be required to tweak the trimming and null replacement functions.