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Tag Archive for data-warehouse

Can a table be both Fact and Dimension

Ok, I am a newbie and don’t really think “dimensionally” yet, I have most of my initial schema roughed out but I keep flipping back and forth on one table.

Data warehouse architecture for mutating schema

I am setting up an ETL process and small data warehouse for querying the data in a few different dimensions. One issue is that the schema for the objects can mutate over time – mainly that some fields will be added and some removed. What are some methodologies or approaches for handling this?

how to express fact table at multiple resolutions

I am creating a dimensional model (data mart) in a data warehouse. I’m running into a design problem involving date resolution. This model will have 2 fact tables: one for actuals, and one for forecast. Actuals in the data source are available at the date resolution of day, whereas forecast in the data source is only available at the date resolution of month. So, I need to express actuals in this mart at the date resolution of month. Actuals are currently saved in another data mart, which means that there is at least potential to re-use that table, but that table is expressed at the date resolution of day, not month. Given that, should I attempt to re-use that table? That is, should I create a view over the actuals table, where I “roll up” date to month? Or, should I create a new actuals table (at the date resolution of month)?

implementing dynamic query handler on historical data

Context: I have historical data about property (house) sales collected from various sources in a centralized/cloud data source (assume info collection is handled by a third party) Planning to develop an application to query and retrieve data from this centralized data source Example Queries: Simple : for given XYZ post code, what is average house […]

New to Data Warehouses/ERP

The organisation I work for is very application rich i.e. there are lots of SQL and Oracle databases. We are thinking about a data warehouse.