Count and Exists

Count

The count function gets the number of matching rows

 let c = Customer[true].count() //total number of customers
 let c2 = Customer[name == 'smith'].count() //number of customers with name 'smith'

Exists

The exists function returns a boolean indicating whether any matching records exist.

 let c = Customer[true].exists() //any customers?
 let c2 = Customer[name == 'smith'].exists() //any customers with name 'smith'?