Dimension tables
A dimension table is a table that stores the textual descriptions of the dimensions of the business. A dimension table contains an element and an attribute, if appropriate, for each level in the hierarchy.
The lowest level of detail that is required for data analysis
determines the lowest level in the hierarchy. Levels higher than this
base level store redundant data. This denormalized table reduces the
number of joins that are required for a query and makes it easier
for users to query at higher levels and then drill down to lower levels
of detail. The term drilling down means to add row headers
from the dimension tables to your query. The following table shows
an example of a dimension table that is based on the Account dimension.
| Acct code | Account name | Territory | Salesman | Region | Region size | Region manager |
|---|---|---|---|---|---|---|
| 1 | Javier's Mfg. | 101 | B. Gupta | Asia-Pacific | Over 50 | T. Sent |
| 2 | TBD Sales | 101 | B. Gupta | Asia-Pacific | Over 50 | T. Sent |
| 3 | Tariq's Wares | 101 | B. Gupta | Asia-Pacific | Over 50 | T. Sent |
| 4 | The Golf Co. | 201 | S. Chiba | Asia-Pacific | Over 50 | T. Sent |