Dimension table | Fact table |
It provides the context /descriptive information for fact table measurements. | It provides measurement of an enterprise. |
Structure of Dimension - Surrogate key, one or more other fields that compose the natural key and set of Attributes. | Structure of Fact Table - foreign key, Degenerated Dimension and Measurements. |
Size of Dimension Table is smaller than Fact Table. | Size of Fact Table is larger than Dimension Table. |
In a schema more no of dimensions tables are presented than Fact tables. | In a schema less no of Fact tables are presented than Dimension tables. |
Values of fields are in text representation. | Values of the fields always in integer form. |
We can load the dimension table directly | We can't load the fact table first. So to load the fact table we need to load the dimension table first. Also while loading the fact table we will make a lookup on the dimension table cause the fact table contains the measures/facts & the foreign keys which are primary keys in the dimension tables surrounded to that fact table. |
Monday, July 12, 2010
What is difference between Fact table and dimension table?
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