A histogram is a chart that shows frequencies for equal width intervals of values of a metric variable. A company wants to know how monthly salaries are distributed over 1,110 employees having operational, middle or higher management level jobs. The screenshot below shows what their raw data look like.
The snowflake schema is a variation of the star schema, featuring normalization of dimension tables. In computing, a snowflake schema is a logical arrangement of tables in a multidimensional database such that the entity relationship diagram resembles a snowflake shape. The snowflake schema is represented by centralized fact tables which are connected to multiple dimensions..
Complex snowflake patterns appears when there are elaborate snowflake schema dimensions. In order for the schema to be the shape of a snowflake, it must consist of various relationship levels, and child tables should include several parent tables. The fact tables are not affected by the snowflaking effect.