Databases 2.3

Fact Table

table containing quantitative data such as sales figures or other measurable metrics

Dimension Table

table that stores additional details about a fact table and it’s data

Star Schema

schema in which dimension tables all stem from one central fact table

Snowflake Schema

schema in which dimensions tables are based on a central fact table but also contain their own subordinate dimension tables

Connection Trap

when complex relationship patterns lead to ambiguous or incorrect query results

Chasm Trap

occurs when two or more fact tables have no direct relationship besides the dimension tables connecting them

Cartesian Product

an over-counting of data on a query that joins two fact tables without a direct relationship

when counting or aggregating

Fan Trap

occurs when there are multiple one-to-many relationships within a parent child relationship

returns incorrect results from joining tables that are not adjacent