Category archive for ‘Personal Data Marts’ 
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Degenerate Dimensions in Datamarts
Not all dimensions are created equal. A typical dimension is defined by a table that holds the reference data that is being joined to the fact data. So in the fact table, for example, we have the product ID, or the product code, and in the product dimension table we have a single row for [...]
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Data Warehouse vs Data Mart
Very often, the question is asked- what's the difference between a data mart and a data warehouse- which of them do I need? Data warehouse or Data Mart? Data Warehouse: Holds multiple subject areas Holds very detailed information Works to integrate all data sources Does not necessarily use a dimensional model but feeds dimensional models. [...]
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Dimensional Tables and Fact Tables
One of the secrets to putting together a good set of data marts is the concept of dimensions. There are two key steps being able to analyse your data, and to build a working data mart model. Build a set of clean, consistent dimension tables that store reference information about your key dimensions like Product, [...]
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Data modelling Hierarchies- how to make a dimension
One of the most useful data model structures in a data mart is a Hierarchy (also called a Tree structure). Tree structures let us take a large number of things and organise them in a way that makes sense. More importantly, a tree structure lets us “drill down” into information. Hierarchy Rules In a simple tree [...]
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Business Intelligence Workspaces and in memory self serve analysis
In the classical Business Intelligence architecture, users sit at their computers, requesting reports and analysis, and huge central servers churn through the numbers. The dual-core machine on the desk with 2Gb of RAM is asked to do almost nothing. As machines get faster and faster, new tools that use memory are going to create functionality and speed that just hasn't been [...]
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Data mart Data Modelling 101
Last time we talked about how much data can comfortably be put into and Excel spreadsheet and I've found that more than a few hundred thousand rows can get awkward. Plus, certain types of operations are more difficult to automate in excel (often requiring programming skills with macros or visual basic for applications (VBA)). So- this means [...]
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Importing Data into Excel
I've seen lots of Business Intelligence (BI) solutions, (data marts, data warehouses and the accompanying reports and dashboards) using all sorts of different tools. But I'll tell you- NO tool has yet been as successful as Microsoft Excel for providing a do it yourself data analysis platform to import data into. Now, I'm not suggesting [...]
