# 2.7 Complex Data Type

A complex data type is contrasted with the simple data types. Where a simple data type has a single value and defined type; a complex data type requires more than one piece of information to complete the description. An example of a complex data type is a measurement.
When you measure something you have the value and the units you measured with. So when you measure the distance between two objects it would be 2.5 feet. Where 2.5 is the value of the measurement and feet is the unit of measure. To capture a measurement you
need the value or number that represents the measurement taken, but you also need to know the unit of measure. A unit of measure is inches, yards, square feet, etc. A complex data type is also a base type. See

7.7 Entities vs. Base Types for more details.