Data Warehousing (RSS)

Too Dim or not Too Dim

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No i'm not talking about a new Harry Enfield sketch about a posh bloke that's a bit thick, I 'm talking about tables in a warehouse.

Many people insist on naming tables DimCustomer, Dim Product etc and FactOrderLine. What is the purpose of this, especially in a UDM model where tables can easily be dimensions and facts. What happens then, should it be DimFactOrder or should it be FactDimOrder, sounds like something from a Chinese menu.

... To read the complete version of this post go here, http://sqlblogcasts.com/blogs/simons/Too Dim or not Too Dim

posted Friday, May 18, 2007 5:54 PM by SimonSabin with 0 Comments

How to speed up partition merging

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The key to performance with partition management is to deal with empty partitions. That way all you have is meta data changes and no data has to be copied.

We recently encountered a situation where we had two partitions and wanted to merge them. In a merge you have 3 boundaries the left one, the middle one and the right one. In doing a merge you are going to get rid of the middle one and have 1 partition that is bounded by the left and right values. The partition on the left of the middle boundary was empty and the one on the right wasn't. We were using RIGHT partitioning so the partition value for the middle boundary was included in the RIGHT hand partition. We expected this to be very quick. The engine you take the RIGHT hand partition and use it for the new partition.

... To read the complete version of this post go here, http://sqlblogcasts.com/blogs/simons/How to speed up partition merging

posted Tuesday, July 31, 2007 11:10 PM by SimonSabin with 0 Comments

Time dimension - What should the key be?

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We are currently implementing a data warehouse and the design of the time dimension was recently being done.

Firstly it was agreed that day and time should be split out. Combining the two into one dimension is nuts your dimension would be huge and unworkable.

... To read the complete version of this post go here, http://sqlblogcasts.com/blogs/simons/Time dimension - What should the key be?

posted Tuesday, June 26, 2007 9:04 AM by SimonSabin with 0 Comments