I was examing the SQL Server offerings that Azure provides and was having trouble finding answers to what some of the metrics meant on each tier, specifically the "Transaction rate per hour" or "Transaction rate per minute". My programming brain immedidately associated "Transaction" with an official database transaction.
In terms of this metric the transaction for this calculation consists of all SELECT, UPDATE, INSERT and DELETES. Further, each of these will be sub categorized based on how much processing each one takes (e.g. simple selects will be weighted less than complex ones).
The best descriptions I could find were here:
This link has a good analysis on the pros/cons/price performance of some of the database tiers: