About Logical Columns

Each logical table contains one or more logical columns. A logical column can be an attribute or a measure that is mapped or calculated.

In most cases you create logical columns by dragging tables from the physical layer to the logical layer. The logical columns you create in this way map to one or more physical columns and they inherit the physical column's data types.

You can also manually create logical columns that are derived from calculations based on other logical columns.

For example, you have a dimension table with two mapped attribute columns: a First Name column and a Last Name column. In the dimension table you can also have a calculated column named Full Name that is calculated by concatenating the Last Name column with the First Name column.

In the same example, you have a fact table with two mapped measure columns: a Revenue measure column with an aggregation of Sum, and a Billed Quantity measure column with an aggregation of Count. In the fact table you can also have a calculated measure column named Actual Unit Price that is calculated by dividing Revenue by Billed Quantity.