Different methods of loading Dimension tables

Conventional Load:

Before loading the data, all the Table constraints will be checked against the data.

Direct load :( Faster Loading)

All the Constraints will be disabled. Data will be loaded directly. Later the data will be checked against the table constraints and the bad data won't be indexed.

Which columns go to the fact table and which columns go the dimension table -

The Aggregation or calculated value columns will go to Fact Table and details information will go to dimensional table.

Degenerate Dimension Table -

• The column in a fact table, that does not map to any dimensions, neither it s a measure column.
• If a table contains the values, which are neither dimensions nor measures is called degenerate dimensions. Ex: invoice id, empno.

Grains or Granularity

              Level of granularity means the upper/lower level of hierarchy, up to which we can see/drill the data in the fact table.

                Level of granularity means level of detail that you put into the fact table in a data warehouse. For example: Based on design you can decide to put the sales data in each transaction. Now, level of granularity would mean what detail you are willing to put for each transactional fact. Product sales with respect to each minute or you want to aggregate it up to minute and put that data.